U.S. Supreme Court Erie Railroad Co. v. Tompkins, 304 U.S.
64 (1938) Erie Railroad Co. v.
Tompkins No. 367 Argued January 31,
1938 Decided April 25,
1938 304 U.S.
64 CERTIORARI TO THE CIRCUIT COURT OF
APPEALS FOR THE SECOND
CIRCUIT Syllabus 1. The liability of a railroad company for injury caused by
negligent operation of its train to a pedestrian on a much-used,
beaten path on its right-of-way along and near the rails depends,
in the absence of a federal or state statute, upon the unwritten
law of the State where the accident occurred. Pp. 304 U. S. 71 et seq. 2. A federal court exercising jurisdiction over such a case on
the ground of diversity of citizenship, is not free to treat this
question as one of so-called "general law," but must apply the
state law as declared by the highest state court. Swift v.
Tyson , 16 Pet. 1, overruled. Id. 3. There is no federal general common law. Congress has no power
to declare substantive rules of common law applicable in a State
whether they be local in their nature or "general," whether they be
commercial law or a part of the law of torts. And no clause in the
Constitution purports to confer such a power upon the federal
courts. Except in matters governed by the Federal Constitution or
by Acts of Congress, the law to be applied in any case is the law
of the State. And whether the law of the State shall be declared by
its legislature in a statute or by its highest court in a decision
is not a matter of federal concern. P. 304 U. S.
78 .

															4. In disapproving the doctrine of Swift v. Tyson, the
Court does not hold unconstitutional § 34 of the Federal Judiciary
Act of 1789 or any other Act of Congress. It merely declares that,
by applying the doctrine of that case, rights which are reserved by
the Constitution to the several States have been invaded. P. 304 U. S.
79 .

															90 F.2d 603, reversed. Page 304 U. S. 65 CERTIORARI, 302 U.S. 671, to review the affirmance of a judgment
recovered against the railroad company in an action for personal
injuries. The accident was in Pennsylvania. The action was in New
York, jurisdiction being based on diversity of citizenship Page 304 U. S. 69 MR. JUSTICE BRANDEIS delivered the opinion of the Court.

															The question for decision is whether the oft-challenged doctrine
of Swift v. Tyson [ Footnote 1 ] shall now be disapproved.

															Tompkins, a citizen of Pennsylvania, was injured on a dark night
by a passing freight train of the Erie Railroad Company while
walking along its right of way at Hughestown in that State. He
claimed that the accident occurred through negligence in the
operation, or maintenance, of the train; that he was rightfully on
the premises as licensee because on a commonly used beaten footpath
which ran for a short distance alongside the tracks, and that he
was struck by something which looked like a door projecting from
one of the moving cars. To enforce that claim, he brought an action
in the federal court for southern New York, which had jurisdiction
because the company is a corporation of that State. It denied
liability, and the case was tried by a jury. Page 304 U. S. 70 The Erie insisted that its duty to Tompkins was no greater than
that owed to a trespasser. It contended, among other things, that
its duty to Tompkins, and hence its liability, should be determined
in accordance with the Pennsylvania law; that, under the law of
Pennsylvania, as declared by its highest court, persons who use
pathways along the railroad right of way -- that is, a longitudinal
pathway, as distinguished from a crossing -- are to be deemed
trespassers, and that the railroad is not liable for injuries to
undiscovered trespassers resulting from its negligence unless it be
wanton or willful. Tompkins denied that any such rule had been
established by the decisions of the Pennsylvania courts, and
contended that, since there was no statute of the State on the
subject, the railroad's duty and liability is to be determined in
federal courts as a matter of general law.

															The trial judge refused to rule that the applicable law
precluded recovery. The jury brought in a verdict of $30,000, and
the judgment entered thereon was affirmed by the Circuit Court of
Appeals, which held, 90 F.2d 603, 604, that it was unnecessary to
consider whether the law of Pennsylvania was as contended, because
the question was one not of local, but of general, law, and
that,

															"upon questions of general law, the federal courts are free, in
the absence of a local statute, to exercise their independent
judgment as to what the law is, and it is well settled that the
question of the responsibility of a railroad for injuries caused by
its servants is one of general law. . . . Where the public has made
open and notorious use of a railroad right of way for a long period
of time and without objection, the company owes to persons on such
permissive pathway a duty of care in the operation of its trains. .
. . It is likewise generally recognized law that a jury may find
that negligence exists toward a pedestrian using a permissive path
on the railroad right of way if he is hit by some object projecting
from the side of the train. " Page 304 U. S. 71 The Erie had contended that application of the Pennsylvania rule
was required, among other things, by § 34 of the Federal Judiciary
Act of September 24, 1789, c. 20, 28 U.S.C. § 725, which
provides:

															"The laws of the several States, except where the Constitution,
treaties, or statutes of the United States otherwise require or
provide, shall be regarded as rules of decision in trials at common
law, in the courts of the United States, in cases where they
apply."

															Because of the importance of the question whether the federal
court was free to disregard the alleged rule of the Pennsylvania
common law, we granted certiorari. First. Swift v. Tyson , 16 Pet. 1, 41 U. S. 18 , held
that federal courts exercising jurisdiction on the ground of
diversity of citizenship need not, in matters of general
jurisprudence, apply the unwritten law of the State as declared by
its highest court; that they are free to exercise an independent
judgment as to what the common law of the State is -- or should be,
and that, as there stated by Mr. Justice Story:

															"the true interpretation of the thirty-fourth section limited
its application to state laws strictly local, that is to say, to
the positive statutes of the state, and the construction thereof
adopted by the local tribunals, and to rights and titles to things
having a permanent locality, such as the rights and titles to real
estate, and other matters immovable and intraterritorial in their
nature and character. It never has been supposed by us that the
section did apply, or was intended to apply, to questions of a more
general nature, not at all dependent upon local statutes or local
usages of a fixed and permanent operation, as, for example, to the
construction of ordinary contracts or other written instruments,
and especially to questions of general commercial law, where the
state tribunals are called upon to perform the like functions as
ourselves, that is, to ascertain upon general reasoning and legal
analogies what is the true exposition of the contract or Page 304 U. S. 72 instrument, or what is the just rule furnished by the principles
of commercial law to govern the case."

															The Court, in applying the rule of § 34 to equity cases, in Mason v. United States, 260 U. S. 545 , 260 U. S. 559 ,
said: "The statute, however, is merely declarative of the rule
which would exist in the absence of the statute." [ Footnote 2 ] The federal courts assumed, in
the broad field of "general law," the power to declare rules of
decision which Congress was confessedly without power to enact as
statutes. Doubt was repeatedly expressed as to the correctness of
the construction given § 34, [ Footnote 3 ] and as to the soundness of the rule which it
introduced. [ Footnote 4 ] But it
was the more recent research of a competent scholar, who examined
the original document, which established that the construction
given to it by the Court was erroneous, and that the purpose of the
section was merely to make certain that, in all matters except
those in which some federal law is controlling, Page 304 U. S. 73 the federal courts exercising jurisdiction in diversity of
citizenship cases would apply as their rules of decision the law of
the State, unwritten as well as written. [ Footnote 5 ]

															Criticism of the doctrine became widespread after the decision
of Black & White Taxicab Co. v. Brown & Yellow Taxicab
Co., 276 U. S. 518 .
[ Footnote 6 ] There, Brown and
Yellow, a Kentucky corporation owned by Kentuckians, and the
Louisville and Nashville Railroad, also a Kentucky corporation,
wished that the former should have the exclusive privilege of
soliciting passenger and baggage transportation at the Bowling
Green, Kentucky, railroad station, and that the Black and White, a
competing Kentucky corporation, should be prevented from
interfering with that privilege. Knowing that such a contract would
be void under the common law of Kentucky, it was arranged that the
Brown and Yellow reincorporate under the law of Tennessee, and that
the contract with the railroad should be executed there. The suit
was then brought by the Tennessee corporation in the federal court
for western Kentucky to enjoin competition by the Black and White;
an injunction issued by the District Court Page 304 U. S. 74 was sustained by the Court of Appeals, and this Court, citing
many decisions in which the doctrine of Swift v. Tyson had
been applied, affirmed the decree. Second. Experience in applying the doctrine of Swift v. Tyson had revealed it defects, political and
social, and the benefits expected to flow from the rule did not
accrue. Persistence of state courts in their own opinions on
questions of common law prevented uniformity; [ Footnote 7 ] and the impossibility of discovering a
satisfactory line of demarcation between the province of general
law and that of local law developed a new well of uncertainties.
[ Footnote 8 ]

															On the other hand, the mischievous results of the doctrine had
become apparent. Diversity of citizenship jurisdiction was
conferred in order to prevent apprehended discrimination in state
courts against those not citizens of the State. Swift v.
Tyson introduced grave discrimination by noncitizens against
citizens. It made rights enjoyed under the unwritten "general law"
vary according to whether enforcement was sought in the state Page 304 U. S. 75 or in the federal court, and the privilege of selecting the
court in which the right should be determined was conferred upon
the noncitizen. [ Footnote 9 ]
Thus, the doctrine rendered impossible equal protection of the law.
In attempting to promote uniformity of law throughout the United
States, the doctrine had prevented uniformity in the administration
of the law of the State.

															The discrimination resulting became, in practice, far-reaching.
This resulted in part from the broad province accorded to the
so-called "general law" as to which federal courts exercised an
independent judgment. [ Footnote
10 ] In addition to questions of purely commercial law, "general
law" was held to include the obligations under contracts entered
into and to be performed within the State, [ Footnote 11 ] the extent to which a carrier
operating within a State may stipulate for exemption from liability
for his own negligence or that of his employee; [ Footnote 12 ] the liability for torts
committed within the State upon person resident or property located
there, even where the question of liability Page 304 U. S. 76 depended upon the scope of a property right conferred by the
State [ Footnote 13 ] and the
right to exemplary or punitive damages. [ Footnote 14 ] Furthermore, state decisions construing
local deeds, [ Footnote 15 ]
mineral conveyances, [ Footnote
16 ] and even devises of real estate [ Footnote 17 ] were disregarded. [ Footnote 18 ]

															In part, the discrimination resulted from the wide range of
persons held entitled to avail themselves of the federal rule by
resort to the diversity of citizenship jurisdiction. Through this
jurisdiction, individual citizens willing to remove from their own
State and become citizen of another might avail themselves of the
federal rule. [ Footnote 19 ]
And, without even change of residence, a corporate citizen of Page 304 U. S. 77 the State could avail itself of the federal rule by
reincorporating under the laws of another State, as was done in the Taxicab case.

															The injustice and confusion incident to the doctrine of Swift v. Tyson have been repeatedly urged as reasons for
abolishing or limiting diversity of citizenship jurisdiction.
[ Footnote 20 ] Other
legislative relief has been proposed. [ Footnote 21 ] If only a question of statutory
construction were involved, we should not be prepared to abandon a
doctrine so widely applied throughout nearly a century. [ Footnote 22 ] But the
unconstitutionality Page 304 U. S. 78 of the course pursued has now been made clear, and compels us to
do so. Third. Except in matters governed by the Federal
Constitution or by Acts of Congress, the law to be applied in any
case is the law of the State. And whether the law of the State
shall be declared by its Legislature in a statute or by its highest
court in a decision is not a matter of federal concern. There is no
federal general common law. Congress has no power to declare
substantive rules of common law applicable in a State, whether they
be local in their nature or "general," be they commercial law or a
part of the law of torts. And no clause in the Constitution
purports to confer such a power upon the federal courts. As stated
by Mr. Justice Field when protesting in Baltimore & Ohio R.
Co. v. Baugh, 149 U. S. 368 , 149 U. S. 401 ,
against ignoring the Ohio common law of fellow servant
liability:

															"I am aware that what has been termed the general law of the
country -- which is often little less than what the judge advancing
the doctrine thinks at the time should be the general law on a
particular subject -- has been often advanced in judicial opinions
of this court to control a conflicting law of a State. I admit that
learned judges have fallen into the habit of repeating this
doctrine as a convenient mode of brushing aside the law of a State
in conflict with their views. And I confess that, moved and
governed by the authority of the great names of those judges, I
have, myself, in many instances, unhesitatingly and confidently,
but I think now erroneously, repeated the same doctrine. But,
notwithstanding the great names which may be cited in favor of the
doctrine, and notwithstanding the frequency with which the doctrine
has been reiterated, there stands, as a perpetual protest against
its repetition, the Constitution of the United States, which
recognizes and preserves the autonomy and independence of the
States -- independence in their legislative and independence Page 304 U. S. 79 in their judicial departments. Supervision over either the
legislative or the judicial action of the States is in no case
permissible except as to matters by the Constitution specifically
authorized or delegated to the United States. Any interference with
either, except as thus permitted, is an invasion of the authority
of the State and, to that extent, a denial of its
independence."

															The fallacy underlying the rule declared in Swift v.
Tyson is made clear by Mr. Justice Holmes. [ Footnote 23 ] The doctrine rests upon the
assumption that there is "a transcendental body of law outside of
any particular State but obligatory within it unless and until
changed by statute," that federal courts have the power to use
their judgment as to what the rules of common law are, and that, in
the federal courts, "the parties are entitled to an independent
judgment on matters of general law":

															"but law in the sense in which courts speak of it today does not
exist without some definite authority behind it. The common law so
far as it is enforced in a State, whether called common law or not,
is not the common law generally, but the law of that State existing
by the authority of that State without regard to what it may have
been in England or anywhere else. . . ."

															"the authority and only authority is the State, and, if that be
so, the voice adopted by the State as its own [whether it be of its
Legislature or of its Supreme Court] should utter the last
word."

															Thus, the doctrine of Swift v. Tyson is, as Mr. Justice
Holmes said,

															"an unconstitutional assumption of powers by courts of the
United States which no lapse of time or respectable array of
opinion should make us hesitate to correct."

															In disapproving that doctrine, we do not hold Page 304 U. S. 80 unconstitutional § 34 of the Federal Judiciary Act of 1789 or
any other Act of Congress. We merely declare that, in applying the
doctrine, this Court and the lower courts have invaded rights
which, in our opinion, are reserved by the Constitution to the
several States. Fourth. The defendant contended that, by the common law
of Pennsylvania as declared by its highest court in Falchetti
v. Pennsylvania R. Co., 307 Pa. 203; 160 A. 859, the only duty
owed to the plaintiff was to refrain from willful or wanton injury.
The plaintiff denied that such is the Pennsylvania law. [ Footnote 24 ] In support of their
respective contentions the parties discussed and cited many
decisions of the Supreme Court of the State. The Circuit Court of
Appeals ruled that the question of liability is one of general law,
and on that ground declined to decide the issue of state law. As we
hold this was error, the judgment is reversed and the case remanded
to it for further proceedings in conformity with our opinion. Reversed. MR. JUSTICE CARDOZO took no part in the consideration or
decision of this case.

															[ Footnote 1 ]

															16 Pet. 1 (1842). Leading cases applying the doctrine are
collected in Black & White Taxicab Co. v. Brown &
Yellow Taxicab Co., 276 U. S. 518 , 276 U. S. 530 , 276 U. S. 531 .
Dissent from its application or extension was expressed as early as
1845 by Mr. Justice McKinley (and Mr. Chief Justice Taney) in Lane v. Vick , 3 How. 464, 44 U. S. 477 .
Dissenting opinions were also written by Mr. Justice Daniel in Rowan v.
Runnels , 5 How. 134, 46 U. S. 140 ;
by Mr. Justice Nelson in Williamson v.
Berry , 8 How. 495, 49 U. S. 550 , 49 U. S. 558 ;
by Mr. Justice Campbell in Pease v. Peck , 18 How. 595, 59 U. S. 599 , 59 U. S. 600 ,
and by Mr. Justice Miller in Gelpcke v. City of
Dubuque , 1 Wall. 175, 68 U. S. 207 ,
and Butz v. City of
Muscatine , 8 Wall. 575, 75 U. S. 585 .
Vigorous attack upon the entire doctrine was made by Mr. Justice
Field in Baltimore & Ohio R. Co. v. Baugh, 149 U. S. 368 , 149 U. S. 390 ,
and by Mr. Justice Holmes in Kuhn v. Fairmont Coal Co., 215 U. S. 349 , 215 U. S. 370 ,
and in the Taxicab Case, 276 U.S. at 276 U. S.
532 .

															[ Footnote 2 ]

															In Hawkins v. Barney's
Lessee , 5 Pet. 457, 30 U. S. 464 ,
it was stated that § 34

															"has been uniformly held to be no more than a declaration of
what the law would have been without it: to-wit, that the lex
loci must be the governing rule of private right, under
whatever jurisdiction private right comes to be examined." See also Bank of Hamilton v. Dudley's
Lessee , 2 Pet. 492, 27 U. S. 525 . Compare Jackson v. Chew, 12 Wheat. 153, 25 U. S. 162 , 25 U. S. 168 ; Livingston v.
Moore , 7 Pet. 469, 32 U. S.
542 .

															[ Footnote 3 ]

															Pepper, The Border Land of Federal and State Decisions (1889)
57; Gray, The Nature and Sources of Law (1909 ed.) §§ 533-34;
Trickett, Non-Federal Law Administered in Federal Courts (1906) 40
Am.L.Rev. 819, 821-24.

															[ Footnote 4 ]

															Street, Is There a General Commercial Law of the United States
(1873) 21 Am.L.Reg. 473; Hornblower, Conflict between State and
Federal Decisions (1880) 14 Am.L.Rev. 211; Meigs, Decisions of the
Federal Courts on Questions of State Law (1882) 8 So.L.Rev. (n.s.)
452, (1911) 45 Am.L.Rev. 47; Heiskell, Conflict between Federal and
State Decisions (1882) 16 Am.L.Rev. 743; Rand, Swift v.
Tyson versus Gelpcke v. Dubuque (1895) 8 Harv.L.Rev.
328, 341-43; Mills, Should Federal Courts Ignore State Laws (1900)
34 Am.L.Rev. 51; Carpenter, Court Decisions and the Common Law
(1917) 17 Col.L.Rev. 593, 602-603.

															[ Footnote 5 ]

															Charles Warren, New Light on the History of the Federal
Judiciary Act of 1789 (1923) 37 Harv.L.Rev. 49, 51-52, 81-88,
108.

															[ Footnote 6 ]

															Shelton, Concurrent Jurisdiction -- Its Necessity and its
Dangers (1928) 15 Va.L.Rev. 137; Frankfurter, Distribution of
Judicial Power Between Federal and State Courts (1928) 13 Corn.L.Q.
499, 524-30; Johnson, State Law and the Federal Courts (1929) 17
Ky.L.J. 355; Fordham, The Federal Courts and the Construction of
Uniform State Laws (1929) 7 N.C.L.Rev. 423; Dobie, Seven
Implications of Swift v. Tyson (1930) 16 Va.L.Rev. 225;
Dawson, Conflict of Decisions between State and Federal Courts in
Kentucky, and the Remedy (1931) 20 Ky.L.J. 1; Campbell, Is Swift v. Tyson an Argument for or against Abolishing
Diversity of Citizenship Jurisdiction (1932) 18 A.B.A.J. 809; Ball,
Revision of Federal Diversity Jurisdiction (1933) 28 Ill.L.Rev.
356, 362-64; Fordham, Swift v. Tyson and the Construction
of State Statutes (1935) 41 W.Va. L.Q. 131.

															[ Footnote 7 ] Compare Mr. Justice Miller in Gelpcke v.
City of Dubuque , 1 Wall. 175, 68 U. S. 209 .
The conflicts listed in Holt, The Concurrent Jurisdiction of the
Federal and State Courts (1888) 160 et seq. cover
twenty-eight pages. See also Frankfurter, supra, note 6 at 524-530; Dawson, supra, note 6; Note Aftermath of the Supreme Court's Stop, Look and Listen Rule (1930)
43 Harv.L.Rev. 926; cf. Yntema and Jaffin, Preliminary
Analysis of Concurrent Jurisdiction (1931) 79 U. of Pa.L.Rev. 869,
881-86. Moreover, as pointed out by Judge Augustus N. Hand in Cole v. Pennsylvania R. Co., 43 F.2d 953, 956-57,
decisions of this Court on common law questions are less likely
than formerly to promote uniformity.

															[ Footnote 8 ] Compare 2 Warren, The Supreme Court in United States
History (rev. ed.1935) 89:

															"Probably no decision of the Court has ever given rise to more
uncertainty as to legal rights, and though doubtless intended to
promote uniformity in the operation of business transactions, its
chief effect has been to render it difficult for business men to
know in advance to what particular topic the Court would apply the
doctrine. . . ."

															The Federal Digest, through the 1937 volume, lists nearly 1000
decisions involving the distinction between questions of general
and of local law.

															[ Footnote 9 ]

															It was even possible for a nonresident plaintiff defeated on a
point of law in the highest court of a State nevertheless to win
out by taking a nonsuit and renewing the controversy in the federal
court. Compare Gardner v. Michigan Cent. R. Co., 150 U. S. 349 ; Harrison v. Foley, 206 Fed. 57 (C.C.A. 8); Interstate
Realty & Inv. Co. v. Bibb County, 293 Fed. 721 (C.C.A. 5); see Mills, supra, note 4 at 52.

															[ Footnote 10 ]

															For a recent survey of the scope of the doctrine, see Sharp & Brennan, The Application of the Doctrine of Swift
v. Tyson since 1900 (1929) 4 Ind.L.J. 367.

															[ Footnote 11 ] Black & White Taxicab Co. v. Brown & Yellow Taxicab
Co., 276 U. S. 518 ; Rowan v.
Runnels , 5 How. 134, 46 U. S. 139 ; Boyce v. Tabb , 18 Wall. 546, 85 U. S. 548 ; Johnson v. Chas. D. Norton Co., 159 Fed. 361 (C.C.A. 6); Keene Five Cent Sav. Bank v. Reid, 123 Fed. 221 (C.C.A.
8).

															[ Footnote 12 ] Railroad Co. v.
Lockwood , 17 Wall. 357, 84 U. S.
367 -368; Liverpool & G. W. Stearn Co. v. Phenix
Ins. Co., 129 U. S. 397 , 129 U. S. 443 ; Eels v. St. Louis, K. & N.W. Ry. Co., 52 Fed. 903
(C.C.S.D. Iowa); Fowler v. Pennsylvania R. Co., 229 Fed.
373 (C.C.A. 2).

															[ Footnote 13 ] Chicago v.
Robbins , 2 Black 418, 67 U. S. 428 . Compare 77 U. S. Milwaukee, 10 Wall. 497, 77 U. S.
506 -507; Yeates v. Illinois Cent. R. Co., 137
Fed. 943 (C.C.N.D.Ill.); Curtis v. Cleveland, C.C. & St. L.
Ry. Co., 140 Fed. 777 (C. G. E.D.Ill.). See also Hough v.
Railway Co., 100 U. S. 213 , 100 U. S. 226 ; Baltimore & Ohio R. Co. v. Baugh, 149 U.
S. 368 ; Gardner v. Michigan Cent. R. Co., 150 U. S. 349 , 150 U. S. 358 ; Beutler v. Grand Trunk Junction Ry. Co., 224 U. S.
85 ; Baltimore & Ohio R. Co. v. Goodman, 275 U. S. 66 ; Pokora v. Wabash Ry. Co., 292 U. S.
98 ; Cole v. Pennsylvania R. Co., 43 F. (2d) 953
(C.C.A. 2).

															[ Footnote 14 ] Lake Shore & M. S. Ry. Co. v. Prentice, 147 U. S. 101 , 147 U. S. 106 ; Norfolk & P. Traction Co. v. Miller, 174 Fed. 607
(C.C.A. 4); Greene v. Keithley, 86 F. (2d) 239 (C.C.A.
8).

															[ Footnote 15 ] Foxcroft v.
Mallet , 4 How. 353, 45 U. S. 379 ; Midland Valley R. Co. v. Sutter, 28 F. (2d) 163 (C.C.A.
8); Midland Valley R. Co. v. Jarvis, 29 F. (2d) 539
(C.C.A. 8).

															[ Footnote 16 ] Kuhn v. Fairmont Coal Co., 215 U.
S. 349 ; Mid-Continent Petroleum Corp. v.
Sauder, 67 F. (2d) 9, 12 (G. C.A. 10), reversed on other
grounds, 292 U. S. 272 .

															[ Footnote 17 ] Lane v. Vick , 3 How. 464, 44 U. S. 476 ; Barber v. Pittsburgh, F. W. & C. R. Co., 166 U. S.
83 , 166 U. S.
99 -100; Messinger v. Anderson, 171 Fed. 785,
791-792 (C.C.A. 6), reversed on other grounds, 225 U. S. 225 U.S.
436; Knox & Lewis v. Alwood, 228 Fed. 753
(S.D.Ga.).

															[ Footnote 18 ] Compare, also, 49 U. S. Berry, 8 How. 495; Watson v.
Tarpley , 18 How. 517; Gelpcke v.
City of Dubuqe , 1 Wall. 175.

															[ Footnote 19 ] See Cheever v.
Wilson , 9 Wall. 108, 76 U. S. 123 ; Robertson v.
Carson , 19 Wall. 94, 86 U. S.
106 -107; Morris v. Gilmer, 129 U.
S. 315 , 129 U. S. 328 ; Dickerman v. Northern Trust Co., 176 U.
S. 181 , 176 U. S. 192 ; Williamson v. Osenton, 232 U. S. 619 , 232 U. S.
625 .

															[ Footnote 20 ] See, e.g., Hearings Before a Subcommittee of the Senate
Committee on the Judiciary on S. 937, S. 939, and S. 3243, 72d
Cong., 1st Sess. (1932) 6-8; Hearing Before the House Committee on
the Judiciary on H.R. 10594, H.R. 4526, and H.R. 11508, 72d Cong.,
1st Sess., ser. 12 (1932) 97-104; Sen.Rep. No. 530, 72d Cong., 1st
Sess. (1932) 4-6; Collier, A Plea Against Jurisdiction Because of
Diversity (1913) 76 Cent.L.J. 263, 264, 266; Frankfurter, supra, note 6; Ball supra, note 6; Warren Corporations and Diversity of Citizenship (1933) 19 Va.L.Rev. 661,
686.

															[ Footnote 21 ]

															Thus, bills which would abrogate the doctrine of Swift v.
Tyson have been introduced. S. 4333, 70th Cong., 1st Sess.; S.
96, 71st Cong., 1st Sess.; H.R. 8094, 72d Cong., 1st Sess. See
also Mills, supra, note 4 at 68-69; Dobie, supra, note 6 at 241; Frankfurter, supra, note 6 at 530; Campbell, supra, note 6 at 811.
State statutes on conflicting questions of "general law" have also
been suggested. See Heiskell, supra, note 4 at 760; Dawson, supra, note 6; Dobie supra, note 6 at 241.

															[ Footnote 22 ]

															The doctrine has not been without defenders. See Eliot,
The Common Law of the Federal Courts (1902) 36 Am.L.Rev. 498,
523-25; A. B. Parker, The Common Law Jurisdiction of the United
States Courts (1907) 17 Yale L.J. 1; Schofield, Swift v.
Tyson: Uniformity of Judge-Made State Law in State and Federal
Courts (1910) 4 Ill.L.Rev. 533; Brown, The Jurisdiction of the
Federal Courts Based on Diversity of Citizenship (1929) 78 U. of
Pa.L.Rev. 179, 189-91; J. J. Parker, The Federal Jurisdiction and
Recent Attacks Upon It (1932) 18 A.B.A.J. 433, 438; Yntema, The
Jurisdiction of the Federal Courts in Controversies Between
Citizens of Different States (1933) 19 A.B.A.J. 71, 74-75; Beutel,
Common Law Judicial Technique and the Law of Negotiable Instruments
-- Two Unfortunate Decisions (1934) 9 Tulane L.Rev. 64.

															[ Footnote 23 ] Kuhn v. Fairmont Coal Co., 215 U.
S. 349 , 215 U. S.
370 -372; Black & White Taxicab Co. v. Brown
& Yellow Taxicab Co., 276 U. S. 518 , 276 U. S.
532 -536.

															[ Footnote 24 ]

															Tompkins also contended that the alleged rule of the Falchetti case is not, in any event, applicable here
because he was struck at the intersection of the longitudinal
pathway and a transverse crossing. The court below found it
unnecessary to consider this contention, and we leave the question
open.

															MR. JUSTICE BUTLER.

															The case presented by the evidence is a simple one. Plaintiff
was severely injured in Pennsylvania. While walking on defendant's
right of way along a much-used path at the end of the crossties of
its main track, he came into collision with an open door swinging
from the side of a car in a train going in the opposite direction.
Having been warned by whistle and headlight, he saw the
locomotive Page 304 U. S. 81 approaching and had time and space enough to step aside and so
avoid danger. To justify his failure to get out of the way, he says
that, upon many other occasions he had safely walked there while
trains passed.

															Invoking jurisdiction on the ground of diversity of citizenship,
plaintiff, a citizen and resident of Pennsylvania, brought this
suit to recover damages against defendant, a New York corporation,
in the federal court for the southern district of that State. The
issues were whether negligence of defendant was a proximate cause
of his injuries and whether negligence of plaintiff contributed. He
claimed that, by hauling the car with the open door, defendant
violated a duty to him. The defendant insisted that it violated no
duty and that plaintiff's injuries were caused by his own
negligence. The jury gave him a verdict on which the trial court
entered judgment; the circuit court of appeals affirmed. 90 F (2d)
603.

															Defendant maintained, citing Falchetti v. Pennsylvania R.
Co., 307 Pa. 203, 160 A. 859, and Koontz v. B. & O. R.
Co., 309 Pa. 122, 163 A. 212, that the only duty owed
plaintiff was to refrain from willfully or wantonly injuring him;
it argued that the courts of Pennsylvania had so ruled with respect
to persons using a customary longitudinal path, as distinguished
from one crossing the track. The plaintiff insisted that the
Pennsylvania decisions did not establish the rule for which the
defendant contended. Upon that issue, the circuit court of appeals
said (p. 604):

															"We need not go into this matter since the defendant concedes
that the great weight of authority in other states is to the
contrary. This concession is fatal to its contention, for upon
questions of general law the federal courts are free, in absence of
a local statute, to exercise their independent judgment as to what
the law is, and it is well settled that the question of the
responsibility of a railroad for injuries caused by its servants is
one of general law. Page 304 U. S. 82 Upon that basis the court held the evidence sufficient to
sustain a finding that plaintiff's injuries were caused by the
negligence of defendant. It also held the question of contributory
negligence one for the jury."

															Defendant's petition for writ of certiorari presented two
questions: whether its duty toward plaintiff should have been
determined in accordance with the law as found by the highest court
of Pennsylvania, and whether the evidence conclusively showed
plaintiff guilty of contributory negligence. Plaintiff contends
that, as always heretofore held by this Court, the issues of
negligence and contributory negligence are to be determined by
general law against which local decisions may not be held
conclusive; that defendant relies on a solitary Pennsylvania case
of doubtful applicability and that, even if the decisions of the
courts of that State were deemed controlling, the same result would
have to be reached.

															No constitutional question was suggested or argued below or
here. And as a general rule, this Court will not consider any
question not raised below and presented by the petition. Olson
v. United States, 292 U. S. 246 , 292 U. S. 262 . Johnson v. Manhattan Ry. Co., 289 U.
S. 479 , 289 U. S. 494 . Gunning v. Cooley, 281 U. S. 90 , 281 U. S. 98 . Here
it does not decide either of the questions presented but, changing
the rule of decision in force since the foundation of the
Government, remands the case to be adjudged according to a standard
never before deemed permissible.

															The opinion just announced states that

															"the question for decision is whether the oft-challenged
doctrine of Swift v. Tyson [1842, 16 Pet.
1] shall now be disapproved."

															That case involved the construction of the Judiciary Act of
1789, § 34:

															"The laws of the several states, except where the Constitution,
treaties, or statutes of the United States otherwise require or
provide, shall be regarded as rules of decision in trials at common
law in the courts of Page 304 U. S. 83 the United States in cases where they apply."

															Expressing the view of all the members of the Court, Mr. Justice
Story said (p. 18):

															"In the ordinary use of language it will hardly be contended
that the decisions of Courts constitute laws. They are, at most,
only evidence of what the laws are, and not of themselves laws.
They are often reexamined, reversed, and qualified by the Courts
themselves, whenever they are found to be either defective, or
ill-founded, or otherwise incorrect. The laws of a state are more
usually understood to mean the rules and enactments promulgated by
the legislative authority thereof, or long established local
customs having the force of laws. In all the various cases,
which have hitherto come before us for decision, this Court have
uniformly supposed that the true interpretation of the
thirty-fourth section limited its application to state laws
strictly local, that is to say, to the positive statutes of the
state, and the construction thereof adopted by the local tribunals,
and to rights and titles to things having a permanent locality,
such as the rights and titles to real estate, and other matters
immovable and intraterritorial in their nature and character. It never has been supposed by us that the section did
apply, or was designed to apply, to questions of a more general
nature, not at all dependent upon local statutes or local usages of
a fixed and permanent operation, as, for example, to the
construction of ordinary contracts or other written instruments,
and especially to questions of general commercial law, where the
state tribunals are called upon to perform the like functions as
ourselves, that is, to ascertain upon general reasoning and legal
analogies, what is the true exposition of the contract or
instrument, or what is the just rule furnished by the principles of
commercial law to govern the case. And we have not now the
slightest difficulty in holding that this section, upon its
true intendment and construction, is strictly limited to local
statutes and local usages of the character Page 304 U. S. 84 before stated, and does not extend to contracts and other
instruments of a commercial nature, the true interpretation and
effect whereof are to be sought not in the decisions of the local
tribunals, but in the general principles and doctrines of
commercial jurisprudence. Undoubtedly, the decisions of the local
tribunals upon such subjects are entitled to, and will receive, the
most deliberate attention and respect of this Court; but they
cannot furnish positive rules, or conclusive authority, by which
our own judgments are to be bound up and governed."

															(Italics added.)

															The doctrine of that case has been followed by this Court in an
unbroken line of decisions. So far as appears, it was not
questioned until more than 50 years later, and then by a single
judge. [ Footnote 2/1 ] Baltimore
& Ohio R. Co. v. Baugh, 149 U. S. 368 , 149 U. S. 390 .
In that case, Mr. Justice Brewer, speaking for the Court, truly
said (p. 149 U. S.
373 ):

															"Whatever differences of opinion may have been expressed have
not been on the question whether a matter of general law should be
settled by the independent judgment of this court, rather than
through an adherence to the decisions of the state courts, but upon
the other question, whether a given matter is one of local or of
general law."

															And since that decision, the division of opinion in this Court
has been one of the same character as it was before. In 1910, Mr.
Justice Holmes, speaking for himself and two other Justices,
dissented from the holding that a Page 304 U. S. 85 court of the United States was bound to exercise its own
independent judgment in the construction of a conveyance made
before the state courts had rendered an authoritative decision as
to its meaning and effect. Kuhn v. Fairmont Coal Co., 215 U. S. 349 . But
that dissent accepted (p. 215 U. S. 371 )
as "settled" the doctrine of Swift v. Tyson, and insisted
(p. 215 U. S. 372 )
merely that the case under consideration was, by nature and
necessity, peculiarly local.

															Thereafter, as before, the doctrine was constantly applied.
[ Footnote 2/2 ] In Black &
White Taxicab Co. v. Brown & Yellow Taxicab Co., 276 U. S. 518 ,
three judges dissented. The writer of the dissent, Mr. Justice
Holmes, said, however (p. 276 U. S.
535 ):

															"I should leave Swift v. Tyson undisturbed, as I
indicated in Kuhn v. Fairmont Coal Co., but I would not
allow it to spread the assumed dominion into new fields."

															No more unqualified application of the doctrine can be found
than in decisions of this Court speaking through Mr. Justice
Holmes. United Zinc Co. v. Britt, 258 U.
S. 268 . Baltimore & Ohio R. Co. v. Goodman, 275 U. S. 66 , 275 U. S. 70 .
Without in the slightest departing from that doctrine, but
implicitly applying it, the strictness of the rule laid down in the Goodman case was somewhat ameliorated by Pokora v.
Wabash Ry. Co., 292 U. S. 98 .

															Whenever possible, consistently with standards sustained by
reason and authority constituting the general law, this Court has
followed applicable decisions of state courts. Mutual Life Ins.
Co. v. Johnson, 293 U. S. 335 , 293 U. S. 339 . See Burgess v. Seligman, 107 U. S. 20 , 107 U. S. 34 . Black & White Taxicab Co. v. Brown & Yellow Taxicab
Co., supra, 276 U. S. 530 .
Unquestionably the issues of negligence and contributory negligence
upon which decision of this case Page 304 U. S. 86 depends are questions of general law. Hough v. Railway
Co., 100 U. S. 213 , 100 U. S. 226 . Lake Shore & M. S. Ry. Co. v. Prentice, 147 U.
S. 101 . Baltimore & Ohio R. Co. v. Baugh,
supra. Gardner v. Michigan Central R. Co., 150 U. S. 349 , 150 U. S. 358 . Central Vermont Ry. Co. v. White, 238 U.
S. 507 , 238 U. S. 512 . Baltimore & Ohio R. Co. v. Goodman, supra. Pokora
v. Wabash Ry. Co., supra. While amendments to § 34 have from time to time been suggested,
the section stands as originally enacted. Evidently Congress has
intended throughout the years that the rule of decision as
construed should continue to govern federal courts in trials at
common law. The opinion just announced suggests that Mr. Warren's
research has established that, from the beginning, this Court has
erroneously construed § 34. But that author's "New Light on the
History of the Federal Judiciary Act of 1789" does not purport to
be authoritative, and was intended to be no more than suggestive.
The weight to be given to his discovery has never been discussed at
this bar. Nor does the opinion indicate the ground disclosed by the
research. In his dissenting opinion in the Taxicab case,
Mr. Justice Holmes referred to Mr. Warren's work, but failed to
persuade the Court that "laws" as used in § 34 included varying and
possibly ill-considered rulings by the courts of a State on
questions of common law. See, e.g., Swift v. Tyson, supra, 117 [argument of counsel -- omitted]. It well may be that, if the
Court should now call for argument of counsel on the basis of Mr.
Warren's research, it would adhere to the construction it has
always put upon § 34. Indeed, the opinion in this case so
indicates. For it declares:

															"If only a question of statutory construction were involved, we
should not be prepared to abandon a doctrine so widely applied
throughout a century. But the unconstitutionality of the course
pursued has now been made clear, and compels us to do so."

															This means that, so far as concerns the rule of decision now
condemned, the Judiciary Act of 1789, passed to establish
judicial Page 304 U. S. 87 courts to exert the judicial power of the United States, and
especially § 34 of that Act as construed, is unconstitutional; that
federal courts are now bound to follow decisions of the courts of
the State in which the controversies arise, and that Congress is
powerless otherwise to ordain. It is hard to foresee the
consequences of the radical change so made. Our opinion in the Taxicab case cites numerous decisions of this Court which
serve in part to indicate the field from which it is now intended
forever to bar the federal courts. It extends to all matters of
contracts and torts not positively governed by state enactments.
Counsel searching for precedent and reasoning to disclose common
law principles on which to guide clients and conduct litigation
are, by this decision, told that, as to all of these questions, the
decisions of this Court and other federal courts are no longer
anywhere authoritative.

															This Court has often emphasized its reluctance to consider
constitutional questions, and that legislation will not be held
invalid as repugnant to the fundamental law if the case may be
decided upon any other ground. In view of grave consequences liable
to result from erroneous exertion of its power to set aside
legislation, the Court should move cautiously, seek assistance of
counsel, act only after ample deliberation, show that the question
is before the Court, that its decision cannot be avoided by
construction of the statute assailed or otherwise, indicate
precisely the principle or provision of the Constitution held to
have been transgressed, and fully disclose the reasons and
authorities found to warrant the conclusion of invalidity. These
safeguards against the improvident use of the great power to
invalidate legislation are so well grounded and familiar that
statement of reasons or citation of authority to support them is no
longer necessary. But see, e.g.: 36 U.
S. Warren Bridge, 11 Pet. 420, 36 U. S. 553 ; Township of Pine Grove v.
Talcott , 19 Wall. 666, 86 U. S. 673 ; Chicago & G. T. Ry. Co. v. Wellman, 143 U.
S. 339 , 143 U. S.
345 ; Page 304 U. S. 88 Baker v. Grice, 169 U. S. 284 , 169 U. S. 292 ; Martin v. District of Columbia, 205 U.
S. 135 , 205 U. S.
140 .

															So far as appears, no litigant has ever challenged the power of
Congress to establish the rule as construed. It has so long endured
that its destruction now without appropriate deliberation cannot be
justified. There is nothing in the opinion to suggest that
consideration of any constitutional question is necessary to a
decision of the case. By way of reasoning, it contains nothing that
requires the conclusion reached. Admittedly, there is no authority
to support that conclusion. Against the protest of those joining in
this opinion, the Court declines to assign the case for reargument.
It may not justly be assumed that the labor and argument of counsel
for the parties would not disclose the right conclusion and aid the
Court in the statement of reasons to support it. Indeed, it would
have been appropriate to give Congress opportunity to be heard
before divesting it of power to prescribe rules of decision to be
followed in the courts of the United States. See Myers v.
United States, 272 U. S. 52 , 272 U. S.
176 .

															The course pursued by the Court in this case is repugnant to the
Act of Congress of August 24, 1937, 50 Stat. 751. It declares:

															"That whenever the constitutionality of any Act of Congress
affecting the public interest is drawn in question in any court of
the United States in any suit or proceeding to which the United
States, or any agency thereof, or any officer or employee thereof,
as such officer or employee, is not a party, the court having
jurisdiction of the suit or proceeding shall certify such fact to
the Attorney General. In any such case, the court shall permit the
United States to intervene and become a party for presentation of
evidence (if evidence is otherwise receivable in such suit or
proceeding) and argument upon the question of the constitutionality
of such Act. In any such suit or proceeding, the United States
shall, subject to the applicable provisions of law, have all the
rights of a Page 304 U. S. 89 party and the liabilities of a party as to court costs to the
extent necessary for a proper presentation of the facts and law
relating to the constitutionality of such Act."

															That provision extends to this Court. § 5. If defendant had
applied for and obtained the writ of certiorari upon the claim
that, as now held, Congress has no power to prescribe the rule of
decision, § 34 as construed, it would have been the duty of this
Court to issue the prescribed certificate to the Attorney General
in order that the United States might intervene and be heard on the
constitutional question. Within the purpose of the statute and its
true intent and meaning, the constitutionality of that measure has
been "drawn in question." Congress intended to give the United
States the right to be heard in every case involving
constitutionality of an Act affecting the public interest. In view
of the rule that, in the absence of challenge of constitutionality,
statutes will not here be invalidated on that ground, the Act of
August 24, 1937, extends to cases where constitutionality is first
"drawn in question" by the Court. No extraordinary or unusual
action by the Court after submission of the cause should be
permitted to frustrate the wholesome purpose of that Act. The duty
it imposes ought here to be willingly assumed. If it were doubtful
whether this case is within the scope of the Act, the Court should
give the United States opportunity to intervene and, if so advised,
to present argument on the constitutional question, for undoubtedly
it is one of great public importance. That would be to construe the
Act according to its meaning.

															The Court's opinion in its first sentence defines the question
to be whether the doctrine of Swift v. Tyson shall now be
disapproved; it recites (p. 304 U. S. 72 )
that Congress is without power to prescribe rules of decision that
have been followed by federal courts as a result of the
construction of § 34 in Swift v. Tyson, and since; after
discussion, it declares (pp. 304 U. S. 77 -78)
that "the unconstitutionality of the course pursued [meaning the
rule of decision Page 304 U. S. 90 resulting from that construction] compels" abandonment of the
doctrine so long applied, and then near the end of the last page
the Court states that it does not hold § 34 unconstitutional, but
merely that, in applying the doctrine of Swift v. Tyson construing it, this Court and the lower courts have invaded rights
which are reserved by the Constitution to the several States. But,
plainly through the form of words employed, the substance of the
decision appears; it strikes down as unconstitutional § 34 as
construed by our decisions; it divests the Congress of power to
prescribe rules to be followed by federal courts when deciding
questions of general law. In that broad field it compels this and
the lower federal courts to follow decisions of the courts of a
particular State.

															I am of opinion that the constitutional validity of the rule
need not be considered, because under the law, as found by the
courts of Pennsylvania and generally throughout the country, it is
plain that the evidence required a finding that plaintiff was
guilty of negligence that contributed to cause his injuries and
that the judgment below should be reversed upon that ground.

															MR. JUSTICE McREYNOLDS concurs in this opinion.

															[ Footnote 2/1 ]

															Mr. Justice Field filed a dissenting opinion, several sentences
of which are quoted in the decision just announced. The dissent
failed to impress any of his associates. It assumes that adherence
to § 34 as construed involves a supervision over legislative or
judicial action of the states. There is no foundation for that
suggestion. Clearly, the dissent of the learned Justice rests upon
misapprehension of the rule. He joined in applying the doctrine for
more than a quarter of a century before his dissent. The reports do
not disclose that he objected to it in any later case. Cf.
Oakes v. Mase, 165 U. S. 363 .

															[ Footnote 2/2 ]

															In Salem Trust Co. v. Manufacturers' Finance Co., 264 U. S. 182 , Mr.
Justice Holmes and Mr. Justice Brandeis concurred (p. 264 U. S. 200 ) in
the judgment of the Court upon a question of general law on the
ground that the rights of the parties were governed by state
law.

															MR. JUSTICE REED.

															I concur in the conclusion reached in this case, in the
disapproval of the doctrine of Swift v. Tyson, and in the
reasoning of the majority opinion except insofar as it relies upon
the unconstitutionality of the "course pursued" by the federal
courts.

															The "doctrine of Swift v. Tyson, " as I understand it,
is that the words "the laws," as used in § 34, line one, of the
Federal Judiciary Act of September 24, 1789, do not include in
their meaning "the decisions of the local tribunals." Mr. Justice
Story, in deciding that point, said (16 Pet. 41 U. S. 19 ): Page 304 U. S. 91 "Undoubtedly, the decisions of the local tribunals upon such
subjects are entitled to, and will receive, the most deliberate
attention and respect of this Court; but they cannot furnish
positive rules, or conclusive authority, by which our own judgments
are to be bound up and governed."

															To decide the case now before us and to "disapprove" the
doctrine of Swift v. Tyson requires only that we say that
the words "the laws" include in their meaning the decisions of the
local tribunals. As the majority opinion shows, by its reference to
Mr. Warren's researches and the first quotation from Mr. Justice
Holmes, that this Court is now of the view that "laws" includes
"decisions," it is unnecessary to go further and declare that the
"course pursued" was "unconstitutional," instead of merely
erroneous.

															The "unconstitutional" course referred to in the majority
opinion is apparently the ruling in Swift v. Tyson that
the supposed omission of Congress to legislate as to the effect of
decisions leaves federal courts free to interpret general law for
themselves. I am not at all sure whether, in the absence of federal
statutory direction, federal courts would be compelled to follow
state decisions. There was sufficient doubt about the matter in
1789 to induce the first Congress to legislate. No former opinions
of this Court have passed upon it. Mr. Justice Holmes evidently saw
nothing "unconstitutional" which required the overruling of Swift v. Tyson, for he said in the very opinion quoted by
the majority, "I should leave Swift v. Tyson undisturbed,
as I indicated in Kuhn v. Fairmont Coal Co., but I would
not allow it to spread the assumed dominion into new fields." Black & White Taxicab Co. v. Brown & Yellow Taxicab
Co., 276 U. S. 518 , 276 U. S. 535 .
If the opinion commits this Court to the position that the Congress
is without power to declare what rules of substantive law shall
govern the federal courts, that conclusion also seems questionable.
The line between procedural and substantive law is hazy, but no one
doubts federal power over procedure. Wayman v.
Southard , 10 Wheat. 1. The Judiciary Article and
the "necessary and proper" clause of Article One may fully
authorize legislation, such as this section of the Judiciary
Act.

															In this Court, stare decisis, in statutory
construction, is a useful rule, not an inexorable command. Burnett v. Coronado Oil & Gas Co., 285 U.
S. 393 , dissent, p. 285 U. S. 406 ,
note 1. Compare Read v. Bishop of Lincoln, [1892] A.C.
644, 655; London Street Tramways Co. v. London County
Council, [1898] A.C. 375, 379. It seems preferable to overturn
an established construction of an Act of Congress, rather than, in
the circumstances of this case, to interpret the Constitution. Cf. United States v. Delaware & Hudson Co., 213 U. S. 366 .

															There is no occasion to discuss further the range or soundness
of these few phrases of the opinion. It is sufficient now to call
attention to them and express my own nonacquiescence.


Klaxon Co. v. Stentor Electric Manufacturing Co., Inc.

U.S. Supreme Court Klaxon Co. v. Stentor Elec. Mfg. Co.,
Inc., 313
U.S. 487 (1941) Klaxon Company v. Stentor Electric
Manufacturing Co., Inc. No. 741 Argued May 1, 2, 1941 Decided June 2, 1941 313
U.S. 487 CERTIORARI TO THE CIRCUIT COURT OF
APPEALS FOR THE THIRD
CIRCUIT Syllabus 1. In diversity of citizenship cases, the federal courts, when
deciding questions of conflict of laws, must follow the rules
prevailing in the States in which they sit. Erie R. Co. v.
Tompkins, 304 U. S. 64 . P. 313 U. S.
496 .

															2. In an action in a federal court. in Delaware, for breach of a
New York contract, the applicability of a New York statute
directing that interest be added to the recovery in contract cases
is a question of conflict of laws, which the federal court must
determine by the law of Delaware. P. 313 U. S.
496 .

															3. The Full Faith and Credit Clause does not require that a
State, contrary to its own policy, shall give effect in actions
brought locally on contracts made in other States, to laws of those
States relating, not to the validity of such contracts, but to the
right to add interest to the recovery as an incidental item of
damages. Page 313 U. S. 488 § 480 N.Y.Civ.Prac. Act. John Hancock Mutual Life Inc. Co.
v. Yates, 299 U. S. 178 ,
distinguished. P. 313 U. S.
497 .

															115 F.2d 268, reversed.

															Certiorari, 312 U.S. 674, to review the affirmance of a judgment
recovered for breach of a contract, 30 F. Supp.
425 . The review in this Court was limited to the question
whether § 480 of the New York Civil Practice Act is applicable to
an action in the federal court in Delaware. Page 313 U. S. 494 MR. JUSTICE REED delivered the opinion of the Court.

															The principal question in this case is whether, in diversity
cases, the federal courts must follow conflict of laws rules
prevailing in the states in which they sit. We left this open in Ruhlin v. New York Life Insurance Co., 304 U.
S. 202 , 304 U. S. 208 ,
note 2. The frequent recurrence of the problem, as well as the
conflict of approach to the problem between the Third Circuit's
opinion here and that of the First Circuit in Sampson v.
Channell, 110 F.2d 754, 759-762, led us to grant
certiorari.

															In 1918, respondent, a New York corporation, transferred its
entire business to petitioner, a Delaware corporation. Petitioner
contracted to use its best efforts to further the manufacture and
sale of certain patented devices covered by the agreement, and
respondent was to have a share of petitioner's profits. The
agreement was executed in New York, the assets were transferred
there, and petitioner began performance there although later it
moved its operations to other states. Respondent was voluntarily
dissolved under New York law in 1919. Ten years later, it
instituted this action in the United States District Court for the
District of Delaware, alleging that petitioner had failed to
perform its agreement to use its best efforts. Jurisdiction rested
on diversity of citizenship. In 1939, respondent recovered a jury
verdict of $100,000, upon which judgment was entered. Respondent
then moved to correct the judgment by adding interest Page 313 U. S. 495 at the rate of six percent from June 1, 1929, the date the
action had been brought. The basis of the motion was the provision
in section 480 of the New York Civil Practice Act directing that,
in contract actions, interest be added to the principal sum
"whether theretofore liquidated or unliquidated." [ Footnote 1 ] The District Court granted the
motion, taking the view that the rights of the parties were
governed by New York law and that, under New York law, the addition
of such interest was mandatory. 30 F. Supp.
425 , 431. The Circuit Court of Appeals affirmed, 115 F.2d 268,
275, and we granted certiorari, limited to the question whether
section 480 of the New York Civil Practice Act is applicable to an
action in the federal court in Delaware. 312 U.S. 674.

															The Circuit Court of Appeals was of the view that, under New
York law, the right to interest before verdict under section 480
went to the substance of the obligation, and that proper
construction of the contract in suit fixed New York as the place of
performance. It then concluded that section 480 was applicable to
the case because

															"it is clear by what we think is undoubtedly the better view of
the law that the rules for ascertaining the measure of damages are
not a matter of procedure at all, but are Page 313 U. S. 496 matters of substance which should be settled by reference to the
law of the appropriate state according to the type of case being
tried in the forum. The measure of damages for breach of a contract
is determined by the law of the place of performance; Restatement,
Conflict of Laws § 413."

															The court referred also to section 418 of the Restatement, which
makes interest part of the damages to be determined by the law of
the place of performance. Application of the New York statute
apparently followed from the court's independent determination of
the "better view," without regard to Delaware law, for no Delaware
decision or statute was cited or discussed.

															We are of opinion that the prohibition declared in Erie R.
Co. v. Tompkins, 304 U. S. 64 ,
against such independent determinations by the federal courts
extends to the field of conflict of laws. The conflict of laws
rules to be applied by the federal court in Delaware must conform
to those prevailing in Delaware's state courts. [ Footnote 2 ] Otherwise, the accident of
diversity of citizenship would constantly disturb equal
administration of justice in coordinate state and federal courts
sitting side by side. See Erie R. Co. v. Tompkins, supra, at 304 U. S. 74 -77.
Any other ruling would do violence to the principle of uniformity
within a state upon which the Tompkins decision is based.
Whatever lack of uniformity this may produce between federal courts
in different states is attributable to our federal system, which
leaves to a state, within the limits permitted by the Constitution,
the right to pursue local policies diverging from those of its
neighbors. It is not for the federal courts to thwart such local
policies by enforcing an independent "general law" of conflict of
laws. Subject only to review by this Court Page 313 U. S. 497 on any federal question that may arise, Delaware is free to
determine whether a given matter is to be governed by the law of
the forum or some other law. Cf. Milwaukee County v. White
Co., 296 U. S. 268 , 296 U. S. 272 .
This Court's views are not the decisive factor in determining the
applicable conflicts rule. Cf. Funkhouser v. J. B. Preston
Co., 290 U. S. 163 . And
the proper function of the Delaware federal court is to ascertain
what the state law is, not what it ought to be.

															Besides these general considerations, the traditional treatment
of interest in diversity cases brought in the federal courts points
to the same conclusion. Section 966 of the Revised Statutes, 28
U.S.C. § 811, relating to interest on judgments, provides that it
be calculated from the date of judgment at such rate as is allowed
by law on judgments recovered in the courts of the state in which
the court is held. In Massachusetts Benefit Association v.
Miles, 137 U. S. 689 ,
this Court held that section 966 did not exclude the allowance of
interest on verdicts as well as judgments, and the opinion observed
that "the courts of the state and the federal courts sitting within
the state should be in harmony upon this point." (P. 137 U. S.
691 .)

															Looking, then, to the Delaware cases, petitioner relies on one
group to support his contention that the Delaware state courts
would refuse to apply § 480 of the New York Civil Practice Act, and
respondent on another to prove the contrary. We make no analysis of
these Delaware decisions, but leave this for the Circuit Court of
Appeals when the case is remanded.

															Respondent makes the further argument that the judgment must be
affirmed because, under the full faith and credit clause of the
Constitution, Art. 4, § 1, the state courts of Delaware would be
obliged to give effect to the New York statute. The argument rests
mainly on the decision of this Court in John
Hancock Mutual Life Ins. Co. v. Yates , Page 313 U. S. 498 299 U. S. 178 ,
where a New York statute was held such an integral part of a
contract of insurance that Georgia was compelled to sustain the
contract under the full faith and credit clause. Here, however,
section 480 of the New York Civil Practice Act is in no way related
to the validity of the contract in suit, but merely to an
incidental item of damages, interest, with respect to which courts
at the forum have commonly been free to apply their own or some
other law as they see fit. Nothing in the Constitution ensures
unlimited extraterritorial recognition of all statutes or of any
statute under all circumstances. Pacific Employers Insurance
Co. v. Industrial Accident Comm'n, 306 U.
S. 493 ; Kryger v. Wilson, 242 U.
S. 171 . The full faith and credit clause does not go so
far as to compel Delaware to apply section 480 if such application
would interfere with its local policy.

															Accordingly, the judgment is reversed and the case remanded to
the Circuit Court of Appeals for decision in conformity with the
law of Delaware. Reversed. [ Footnote 1 ]

															Section 480, New York Civil Practice Act:

															"Interest to be included in recovery. Where in any action,
except as provided in section four hundred eighty-a, final judgment
is rendered for a sum of money awarded by a verdict, report, or
decision, interest upon the total amount awarded, from the time
when the verdict was rendered or the report or decision was made to
the time of entering judgment, must be computed by the clerk, added
to the total amount awarded, and included in the amount of the
judgment. In every action wherein any sum of money shall be awarded
by verdict, report, or decision upon a cause of action for the
enforcement of or based upon breach of performance of a contract,
express or implied, interest shall be recovered upon the principal
sum, whether theretofore liquidated or unliquidated, and shall be
added to and be a part of the total sum awarded."

															[ Footnote 2 ]

															An opinion in Sampson v. Channell, 110 F.2d 754,
759-762, reaches the same conclusion, as does an opinion of the
Third Circuit handed down subsequent to the case at bar, Waggaman v. General Finance Co., 116 F.2d 254, 257. See also Goodrich, Conflict of Laws, § 12.