OCTOBER TERM, 1999

															Syllabus

															CHRISTENSEN ET AL. v. HARRIS COUNTY ET AL.

															CERTIORARI TO THE UNITED STATES COURT OF APPEALS FOR THE FIFTH
CIRCUIT No. 98-1167. Argued February 23, 2000-Decided May 1,2000 The Fair Labor Standards Act of 1938 (FLSA), 29 U. S. C. § 201(0), permits States and their political subdivisions to
compensate their employees for overtime work by granting them
compensatory time in lieu of cash payment. If the employees do not
use their accumulated compensatory time, the employer must pay cash
compensation under certain circumstances. §§207(0)(3)-(4). Fearing the consequences of having to pay for accrued compensatory
time, Harris County adopted a policy requiring its employees to
schedule time off in order to reduce the amount of accrued time.
Petitioners, county deputy sheriffs, sued, claiming that the FLSA
does not permit an employer to compel an employee to use
compensatory time in the absence of an agreement permitting the
employer to do so. The District Court granted petitioners summary
judgment and entered a declaratory judgment that the policy
violated the FLSA. The Fifth Circuit reversed, holding that the
FLSA did not speak to the issue and thus did not prohibit the
county from implementing its policy. Held: Nothing in the FLSA or its implementing regulations
prohibits a public employer from compelling the use of compensatory
time. Petitioners' claim that § 207(0 )(5) implicitly
prohibits compelled use of compensatory time in the absence of an
agreement is unpersuasive. The proposition that when a statute
limits a thing to be done in a particular mode, it includes a
negative of any other mode, Raleigh & Gaston R.
Co. v. Reid, 13 Wall. 269, 270, does not resolve this
case in petitioners' favor. Section 207(0)(5) provides that
an employee who requests to use compensatory time must be permitted
to do so unless the employer's operations would be unduly
disrupted. The negative inference to be drawn is only that an
employer may not deny a request for a reason other than that
provided in §207(0)(5). Section 207(0)(5) simply
ensures that an employee receive some timely benefit for overtime
work. The FLSA's nearby provisions reflect a similar concern. At
bottom, the best reading of the FLSA is that it ensures liquidation
of compensatory time; it says nothing about restricting an
employer's efforts to re quire employees to use the time.
Because the statute is silent on this issue and because the
county's policy is entirely compatible with § 207(0 )(5),
petitioners cannot, as § 216(b) requires, prove that the county 577 has violated § 207. Two other features of the FLSA support this
interpretation: Employers are permitted to decrease the number of
hours that employees work, and employers also may cash out
accumulated compensatory time by paying the employee his regular
hourly wage for each hour accrued. The county's policy merely
involves doing both of these steps at once. A Department of Labor
opinion letter taking the position that an employer may compel the
use of compensatory time only if the employee has agreed in advance
to such a practice is not entitled to deference under Chevron
U. S. A. Inc. v. Natural Resources Defense Council,
Inc., 467 U. S.
837 . Interpretations such as those in opinion letters-like
interpretations contained in policy statements, agency manuals, and
enforcement guidelines, all of which lack the force of law-do not
warrant Chevron-style deference. They are "entitled to
respect," but only to the extent that they are persuasive, Skidmore v. Swift & Co., 323 U. S. 134 , 140, which
is not the case here. Chevron deference does apply to an
agency interpretation contained in a regulation, but nothing in the
Department of Labor's regulation even arguably requires that an
employer's compelled use policy must be included in an
agreement. And deference to an agency's interpretation of its
regulation is warranted under Auer v. Robbins, 519 U. S. 452 ,
461, only when the regulation's language is ambiguous, which is not
the case here. Pp. 582-588. 158 F.3d
241 , affirmed.

															THOMAS, J., delivered the opinion of the Court, in which
REHNQUIST, C. J., and O'CONNOR, KENNEDY, and SOUTER, JJ., joined,
and in which SCALIA, J., joined except as to Part III. SOUTER, J.,
filed a concurring opinion, post, p. 589. SCALIA, J., filed
an opinion concurring in part and concurring in the judgment, post, p. 589. STEVENS, J., filed a dissenting opinion, in
which GINSBURG and BREYER, JJ., joined, post, p. 592.
BREYER, J., filed a dissenting opinion, in which GINSBURG, J.,
joined, post, p. 596. Michael T. Leibig argued the cause for petitioners. With
him on the briefs were Richard H. Cobb and Murray E.
Malakoff Matthew D. Roberts argued the cause for the United States as
amicus curiae urging reversal. On the brief were Solicitor General
Waxman, Deputy Solicitor General Kneedler, Jonathan E.
Nuechterlein, Allen H. Feldman, and Edward D. Sieger. 578 Michael P. Fleming argued the cause for respondents.

															With him on the brief were Michael A. Stafford, Bruce S. Powers,
and William John Bux.*

															JUSTICE THOMAS delivered the opinion of the Court. Under the
Fair Labor Standards Act of 1938 (FLSA), 52 Stat. 1060, as amended,
29 U. S. C. § 201 et seq. (1994 ed. and Supp. III), States
and their political subdivisions may compensate their employees for
overtime by granting them compensatory time or "comp time," which
entitles them to take time off work with full pay. § 207(0). If the
employees do not use their accumulated compensatory time, the
employer is obligated to pay cash compensation under certain
circumstances. §§ 207(0)(3)-(4). Fearing the fiscal consequences of
having to pay for accrued compensatory time, Harris County adopted
a policy requiring its employees to schedule time off in order to
reduce the amount of accrued compensatory time. Employees of the
Harris County Sheriff's Department sued, claiming that the FLSA
prohibits such a policy. The Court of Appeals rejected their claim.
Finding that nothing in the FLSA or its implementing regulations
prohibits an employer from compelling the use of compensatory time,
we affirm.

															I A

															The FLSA generally provides that hourly employees who work in
excess of 40 hours per week must be compensated

															*Briefs of amici curiae urging reversal were filed for
the American Federation of Labor and Congress of Industrial
Organizations by Jonathan P. Hiatt, Deborah Greenfield, James B.
Coppess, and Laurence Gold; for the International
Association of Fire Fighters by Thomas A. Woodley; and for
the National Association of Police Organizations by Stephen R.
McSpadden. Jeffrey A. Hollingsworth filed a brief for Spokane Valley
Fire Protection District No.1 as amicus curiae urging
affirmance. 579 for the excess hours at a rate not less than 1lf2 times their
regular hourly wage. § 207(a)(1). Although this requirement did not
initially apply to public-sector employers, Congress amended the
FLSA to subject States and their political subdivisions to its
constraints, at first on a limited basis, see Fair Labor Standards
Amendments of 1966, Pub. L. 89-601, § 102(b), 80 Stat. 831
(extending the FLSA to certain categories of state and local
employees), and then more broadly, see Fair Labor Standards
Amendments of 1974, Pub. L. 93-259, §§ 6(a)(1)-(2), 88 Stat. 58-59
(extending the FLSA to all state and local employees, save elected
officials and their staffs). States and their political
subdivisions, however, did not feel the full force of this latter
extension until our decision in Garcia v. San Antonio
Metropolitan Transit Authority, 469 U. S. 528 (1985), which
overruled our holding in National League of Cities v. Usery, 426 U.
S. 833 (1976), that the FLSA could not constitutionally
restrain traditional governmental functions.

															In the months following Garcia, Congress acted to
mitigate the effects of applying the FLSA to States and their
political subdivisions, passing the Fair Labor Standards Amendments
of 1985, Pub. L. 99-150, 99 Stat. 787. See generally Moreau v. Klevenhagen, 508 U. S. 22 , 26 (1993).
Those amendments permit States and their political subdivisions to
compensate employees for overtime by granting them compensatory
time at a rate of 1lf2 hours for every hour worked. See 29 U. S. C.
§ 207(0)(1). To provide this form of compensation, the employer
must arrive at an agreement or understanding with employees that
compensatory time will be granted instead of cash compensation.1
§207(0)(2); 29 CFR § 553.23 (1999).

															1 Such an agreement or understanding need not be formally
reached and memorialized in writing, but instead can be arrived at
informally, such as when an employee works overtime knowing that
the employer rewards overtime with compensatory time. See 29 CFR §
553.23(c)(1) (1999). 580 The FLSA expressly regulates some aspects of accrual and
preservation of compensatory time. For example, the FLSA provides
that an employer must honor an employee's request to use
compensatory time within a "reasonable period" of time following
the request, so long as the use of the compensatory time would not
"unduly disrupt" the employer's operations. § 207(0)(5); 29 CFR §
553.25 (1999). The FLSA also caps the number of compensatory time
hours that an employee may accrue. After an employee reaches that
maximum, the employer must pay cash compensation for additional
overtime hours worked. §207(0)(3)(A). In addition, the FLSA permits
the employer at any time to cancel or "cash out" accrued
compensatory time hours by paying the employee cash compensation
for unused compensatory time. § 207(0)(3)(B); 29 CFR § 553.26(a)
(1999). And the FLSA entitles the employee to cash payment for any
accrued compensatory time remaining upon the termination of
employment. § 207(0)(4).

															B

															Petitioners are 127 deputy sheriffs employed by respondents
Harris County, Texas, and its sheriff, Tommy B. Thomas
(collectively, Harris County). It is undisputed that each of the
petitioners individually agreed to accept compensatory time, in
lieu of cash, as compensation for overtime.

															As petitioners accumulated compensatory time, Harris County
became concerned that it lacked the resources to pay monetary
compensation to employees who worked overtime after reaching the
statutory cap on compensatory time accrual and to employees who
left their jobs with sizable reserves of accrued time. As a result,
the county began looking for a way to reduce accumulated
compensatory time. It wrote to the United States Department of
Labor's Wage and Hour Division, asking "whether the Sheriff may
schedule non-exempt employees to use or take compensatory time."
Brief for Petitioners 18-19. The Acting Administrator of the
Division replied: 581 "[I]t is our position that a public employer may schedule its
nonexempt employees to use their accrued FLSA compensatory time as
directed if the prior agreement specifically provides such a
provision .... "Absent such an agreement, it is our position that neither the
statute nor the regulations permit an employer to require an
employee to use accrued compensatory time." Opinion Letter from
Dept. of Labor, Wage and Hour Div. (Sept. 14, 1992), 1992 WL 845100
(Opinion Letter). After receiving the letter, Harris County implemented a policy
under which the employees' supervisor sets a maximum number of
compensatory hours that may be accumulated. When an employee's
stock of hours approaches that maximum, the employee is advised of
the maximum and is asked to take steps to reduce accumulated
compensatory time. If the employee does not do so voluntarily, a
supervisor may order the employee to use his compensatory time at
specified times.

															Petitioners sued, claiming that the county's policy violates the
FLSA because § 207(o)(5)-which requires that an employer reasonably
accommodate employee requests to use compensatory time-provides the
exclusive means of utilizing accrued time in the absence of an
agreement or understanding permitting some other method. The
District Court agreed, granting summary judgment for petitioners
and entering a declaratory judgment that the county's policy
violated the FLSA. Moreau v. Harris County, 945 F.
Supp. 1067 (SD Tex. 1996). The Court of Appeals for the Fifth
Circuit reversed, holding that the FLSA did not speak to the issue
and thus did not prohibit the county from implementing its
compensatory time policy. Moreau v. Harris County, 158 F.3d
241 (1998). Judge Dennis concurred in part and dissented in
part, concluding that the employer could not compel the employee to
use compensatory time unless the employee agreed to such an
arrangement in advance. Id., 582 at 247-251. We granted certiorari because the Courts of Appeals
are divided on the issue.2 528 U. S. 926 (1999).

															II

															Both parties, and the United States as amicus curiae, concede that nothing in the FLSA expressly prohibits a State or
subdivision thereof from compelling employees to utilize accrued
compensatory time. Petitioners and the United States, however,
contend that the FLSA implicitly prohibits such a practice in the
absence of an agreement or understanding authorizing compelled
use.3 Title 29 U. S. C. § 207(0)(5) provides: "An employee ... "(A) who has accrued compensatory time off ... , and "(B) who
has requested the use of such compensatory time, "shall be permitted by the employee's employer to use such time
within a reasonable period after making the request if the use of
the compensatory time does not unduly disrupt the operations of the
public agency." Petitioners and the United States rely upon the canon ex pressio unius est exclusio alterius, contending
that the express grant of control to employees to use compensatory
time, subject to the limitation regarding undue disruptions

															2 Compare, e. g., Collins v. Lobdell, 188 F.3d
1124 , 1129-1130 (CA9 1999) (upholding employer's policy
compelling compensatory time use), with Heaton v. Moore, 43 F.3d
1176 , 1180-1181 (CA8 1994) (striking down policy
compelling compensatory time use), cert. denied sub nom.
Schriro v. Heaton, 515 U. S. 1104 (1995).

															3 We granted certiorari on the question" '[w]hether a public
agency governed by the compensatory time provisions of the Fair
Labor Standards Act of 1938, 29 U. S. C. §207(o), may,
absent a preexisting agreement, require its employees to use
accrued compensatory time?'" 528 U. S. 926, 927 (1999). As such, we
decide this case on the assumption that no agreement or
understanding exists between the employer and employees on the
issue of compelled use of compensatory time. 583 of workplace operations, implies that all other methods of
spending compensatory time are precluded.4

															We find this reading unpersuasive. We accept the proposition
that "[w]hen a statute limits a thing to be done in a particular
mode, it includes a negative of any other mode." Raleigh & Gaston R. Co. v. Reid, 13 Wall. 269, 270
(1872). But that canon does not resolve this case in petitioners'
favor. The "thing to be done" as defined by § 207(0)(5) is not the
expenditure of compensatory time, as petitioners would have it.
Instead, § 207(0)(5) is more properly read as a minimal guarantee
that an employee will be able to make some use of compensatory time
when he requests to use it. As such, the proper expressio
unius inference is that an employer may not, at least in the
absence of an agreement, deny an employee's request to use
compensatory time for a reason other than that provided in §
207(0)(5). The canon's application simply does not prohibit an
employer from telling an employee to take the benefits of
compensatory time by scheduling time off work with full pay.

															In other words, viewed in the context of the overall statutory
scheme, §207(0)(5) is better read not as setting forth the
exclusive method by which compensatory time can be used, but as
setting up a safeguard to ensure that an em-

															4JUSTICE STEVENS asserts that the parties never make this
argument.

															See post, at 593, n. 1 (dissenting opinion). Although the
United States and petitioners fail to make their arguments in
Latin, we believe a fair reading of the briefs reveals reliance
upon the expressio unius canon. See Brief for United States
as Amicus Curiae 16 ("Congress ... identified only one
circumstance in which an employer may exercise some measure of
control: when an employee requests the use of compensatory time,
the employer must allow such use within a reasonable period of time
except where the use would 'unduly disrupt' the employer's
operations. 29 U. S. C. 207(0)(5). If Congress had intended
for employers to exercise unilateral control over the use of
compensatory time in other respects as well, it presumably would
have so provided"); Reply Brief for Petitioners 4-6 (contending
that the FLSA explicitly provides methods for reducing compensatory
time and thus other means may not be used). 584 ployee will receive timely compensation for working overtime.
Section 207(0)(5) guarantees that, at the very minimum, an employee
will get to use his compensatory time (i. e., take time off
work with full pay) unless doing so would disrupt the employer's
operations. And it is precisely this concern over ensuring that
employees can timely "liquidate" compensatory time that the
Secretary of Labor identified in her own regulations governing
§207(0)(5): "Compensatory time cannot be used as a means to avoid statutory
overtime compensation. An employee has the right to use
compensatory time earned and must not be coerced to accept more
compensatory time than an employer can realistically and in good
faith expect to be able to grant within a reasonable period of his
or her making a request for use of such time." 29 CFR § 553.25(b)
(1999). This reading is confirmed by nearby prOVlSlons of the FLSA that
reflect a similar concern for ensuring that the employee receive
some timely benefit for overtime work. For example, § 207(0)(3)(A)
provides that workers may not accrue more than 240 or 480 hours of
compensatory time, depending upon the nature of the job. See also
§207(0)(2)(B) (conditioning the employer's ability to provide
compensatory time upon the employee not accruing compensatory time
in excess of the § 207(0 )(3)(A) limits). Section 207(0 )(3)(A)
helps guarantee that employees only accrue amounts of compensatory
time that they can reasonably use. After all, an employer does not
need § 207(0)(3)(A)'s protection; it is free at any time to reduce
the number of hours accrued by exchanging them for cash payment, §
207(0)(3)(B), or by halting the accrual of compensatory time by
paying cash compensation for overtime work, 29 CFR § 553.26(a)
(1999). Thus, § 207(0)(3)(A), like § 207(0)(5), reflects a concern
that employees receive some timely benefit in exchange for overtime
work. Moreover, on petitioners' view, the compensa- 585 tory time exception enacted by Congress in the wake of Garcia would become a nullity when employees who refuse to
use compensatory time reach the statutory maximums on accrual.
Petitioners' position would convert § 207(0)(3)(A)'s shield into a
sword, forcing employers to pay cash compensation instead of
providing compensatory time to employees who work overtime.

															At bottom, we think the better reading of § 207(0)(5) is that it
imposes a restriction upon an employer's efforts to prohibit the use of compensatory time when employees request to do so; that
provision says nothing about restricting an employer's efforts to require employees to use compensatory time. Because the
statute is silent on this issue and because Harris County's policy
is entirely compatible with § 207(0)(5), petitioners cannot, as
they are required to do by 29 U. S. C. § 216(b), prove that Harris
County has violated §207.

															Our interpretation of §207(0)(5)-one that does not prohibit
employers from forcing employees to use compensatory time-finds
support in two other features of the FLSA. First, employers remain
free under the FLSA to decrease the number of hours that employees
work. An employer may tell the employee to take off an afternoon, a
day, or even an entire week. Cf. Barrentine v. Arkansas-Best Freight System, Inc., 450 U. S. 728 , 739 (1981)
("[T]he FLSA was designed ... to ensure that each employee covered
by the Act ... would be protected from the evil of overwork ... "
(internal quotation marks and emphasis omitted)). Second, the FLSA
explicitly permits an employer to cash out accumulated compensatory
time by paying the employee his regular hourly wage for each hour
accrued. § 207(0)(3)(B); 29 CFR § 553.27(a) (1999). Thus, under the
FLSA an employer is free to require an employee to take time off
work, and an employer is also free to use the money it would have
paid in wages to cash out accrued compensatory time. The compelled
use of compensatory time challenged in this case 586 merely involves doing both of these steps at once. It would make
little sense to interpret § 207(0)(5) to make the combination of
the two steps unlawful when each independently is lawful.5

															III

															In an attempt to avoid the conclusion that the FLSA does not
prohibit compelled use of compensatory time, petitioners and the
United States contend that we should defer to the Department of
Labor's opinion letter, which takes the position that an employer
may compel the use of compensatory time only if the employee has
agreed in advance to such a practice. Specifically, they argue that
the agency opinion letter is entitled to deference under our
decision in Chevron U. S. A. Inc. v. Natural
Resources Defense Council, Inc., 467 U. S. 837 (1984). In Chevron, we held that a court must give

															5 JUSTICE STEVENS does not dispute this argument. In fact, he
expressly endorses half of it. See post, at 594, 595
(employer free to cash out compensatory time). Instead, JUSTICE
STEVENS claims that we "stumbl[e]" by failing to identify "the
relevant general rule" that employees have "a statutory right to
compensation for overtime work payable in cash." Post, at
592. We fail to do so only because the general rule is not relevant
to this case. Both parties to this case agreed that compensatory
time would be provided in lieu of cash and thus § 207(a)'s general
requirement of cash compensation is supplanted. Petitioners and the
United States do assert that the requirement of cash compensation
is relevant by analogy. They claim that an employer cannot compel
compensatory time use because compensatory time should be treated
like employee cash in the bank-that is, under the exclusive control
of the employee. But this analogy is wholly inapt under the very
terms of the FLSA. The FLSA grants significant control to the
employer over accrued compensatory time. For example, the employer
is free to buyout compensatory time at any time by providing cash
compensation. §207(0)(3)(B); 29 CFR § 553.27(a) (1999).
Additionally, an employer is free to deny any request to use
compensatory time when such use would unduly disrupt the employer's
operations. § 207(0 )(5)(B); 29 CFR § 553.25(d) (1999). The
cash analogy is therefore directly undermined by unambiguous
provisions of the statute. 587 effect to an agency's regulation containing a reasonable
interpretation of an ambiguous statute. Id., at 842-844.

															Here, however, we confront an interpretation contained in an
opinion letter, not one arrived at after, for example, a formal
adjudication or notice-and-comment rulemaking. Interpretations such
as those in opinion letters-like interpretations contained in
policy statements, agency manuals, and enforcement guidelines, all
of which lack the force of lawdo not warrant Chevron-style deference. See, e. g., Reno v. Koray, 515 U. S. 50 , 61 (1995)
(internal agency guideline, which is not "subject to the rigors of
the Administrative Procedur[e] Act, including public notice and
comment," entitled only to "some deference" (internal quotation
marks omitted)); EEOC v. Arabian American Oil Co., 499 U. S. 244 ,
256-258 (1991) (interpretative guidelines do not receive Chevron deference); Martin v. Occupational Safety
and Health Review Comm'n, 499 U. S. 144 , 157 (1991)
(interpretative rules and enforcement guidelines are "not entitled
to the same deference as norms that derive from the exercise of the
Secretary's delegated lawmaking powers"). See generally 1 K. Davis
& R. Pierce, Administrative Law Treatise § 3.5 (3d ed. 1994).
Instead, interpretations contained in formats such as opinion
letters are "entitled to respect" under our decision in Skidmore v. Swift & Co., 323 U. S. 134 , 140
(1944), but only to the extent that those interpretations have the
"power to persuade," ibid. See Arabian American Oil Co.,
supra, at 256-258. As explained above, we find unpersuasive the
agency's interpretation of the statute at issue in this case.

															Of course, the framework of deference set forth in Chevron does apply to an agency interpretation contained in
a regulation. But in this case the Department of Labor's regulation
does not address the issue of compelled compensatory time. The
regulation provides only that "[t]he agreement or understanding
[between the employer and employee] may include other
provisions governing the preservation, use, or cashing 588 out of compensatory time so long as these provisions are
consistent with [§ 207(0)]." 29 CFR § 553.23(a)(2) (1999) (emphasis
added). Nothing in the regulation even arguably requires that an
employer's compelled use policy must be included in an
agreement. The text of the regulation itself indicates that its
command is permissive, not mandatory.

															Seeking to overcome the regulation's obvious meaning, the United
States asserts that the agency's opinion letter interpreting the
regulation should be given deference under our decision in Auer v. Robbins, 519 U. S. 452 (1997). In Auer, we held that an agency's interpretation of its own
regulation is entitled to deference. Id., at 461. See also Bowles v. Seminole Rock & Sand Co., 325 U. S. 410 (1945). But Auer deference is warranted only when the
language of the regulation is ambiguous. The regulation in this
case, however, is not ambiguous-it is plainly permissive. To defer
to the agency's position would be to permit the agency, under the
guise of interpreting a regulation, to create de facto a new
regulation. Because the regulation is not ambiguous on the issue of
compelled compensatory time, Auer deference is
unwarranted.

															***

															As we have noted, no relevant statutory prOVISIOn expressly or
implicitly prohibits Harris County from pursuing its policy of
forcing employees to utilize their compensatory time. In its
opinion letter siding with the petitioners, the Department of Labor
opined that "it is our position that neither the statute nor the
regulations permit an employer to require an employee to use
accrued compensatory time." Opinion Letter (emphasis added). But
this view is exactly backwards. Unless the FLSA prohibits respondents from adopting its policy, petitioners cannot show that
Harris County has violated the FLSA. And the FLSA contains no such
prohibition. The judgment of the Court of Appeals is affirmed.

															It is so ordered. 589 JUSTICE SOUTER, concurring.

															I join the opinion of the Court on the assumption that it does
not foreclose a reading of the Fair Labor Standards Act of 1938
that allows the Secretary of Labor to issue regulations limiting
forced use.

															JUSTICE SCALIA, concurring in part and concurring in the
judgment.

															I join the judgment of the Court and all of its opinion except
Part III, which declines to give effect to the position of the
Department of Labor in this case because its opinion letter is
entitled only to so-called "Skidmore deference," see Skidmore v. Swift & Co., 323 U. S. 134 , 140
(1944). Skidmore deference to authoritative agency views is
an anachronism, dating from an era in which we declined to give
agency interpretations (including interpretive regulations, as
opposed to "legislative rules") authoritative effect. See EEOC v. Arabian American Oil Co., 499 U. S. 244 , 259 (1991)
(SCALIA, J., concurring in part and concurring in judgment). This
former judicial attitude accounts for that provision of the 1946
Administrative Procedure Act which exempted "interpretative rules"
(since they would not be authoritative) from the notice-and-comment
requirements applicable to rulemaking, see 5 U. S. C. §
553(b)(A).

															That era came to an end with our watershed decision in Chevron U. S. A. Inc. v. Natural Resources Defense
Council, Inc., 467 U. S. 837 , 844
(1984), which established the principle that "a court may not
substitute its own construction of a statutory provision for a
reasonable interpretation made by the administrator of an agency."
* While Chevron in fact

															*1 do not comprehend JUSTICE BREYER'S contention, post, at 596-597 (dissenting opinion), that Skidmore deference-that special respect one gives to the interpretive views
of the expert agency responsible for administering the statute-is
not an anachronism because it may apply in "circumstances in which Chevron-type deference is inapplicable." Chevron- 590 Opinion of SCALIA, J.

															involved an interpretive regulation, the rationale of the case
was not limited to that context: "'The power of an administrative
agency to administer a congressionally created ... program
necessarily requires the formulation of policy and the making of
rules to fill any gap left, implicitly or explicitly, by
Congress.'" Id., at 843, quoting Morton v. Ruiz,
415 U. S. 199, 231 (1974). Quite appropriately, therefore, we
have accorded Chevron deference not only to agency
regulations, but to authoritative agency positions set forth in a
variety of other formats. See, e. g., INS v. Aguirre-Aguirre, 526 U. S. 415 , 425 (1999)
(adjudication); NationsBank of N. c., N. A. v. Variable Annuity Life Ins. Co., 513 U. S. 251 , 256-257
(1995) (letter of Comptroller of the Currency); Pen sion
Benefit Guaranty Corporation v. LTV Corp., 496 U. S. 633 , 647-648
(1990) (decision by Pension Benefit Guaranty Corp. to restore
pension benefit plan); Young v. Community Nutrition
Institute, 476 U.
S. 974 , 978-979 (1986) (Food and

															type deference can be inapplicable for only three reasons: (1)
the statute is unambiguous, so there is no room for administrative
interpretation; (2) no interpretation has been made by personnel of
the agency responsible for administering the statute; or (3) the
interpretation made by such personnel was not authoritative, in the
sense that it does not represent the official position of the
expert agency. All of these reasons preclude Skidmore deference as well. The specific example of the inapplicability of Chevron that JUSTICE BREYER posits, viz., "where one has
doubt that Congress actually intended to delegate interpretive
authority to the agency," post, at 597, appears to assume
that, after finding a statute to be ambiguous, we must ask in
addition, before we can invoke Chevron deference, whether
Congress intended the ambiguity to be resolved by the administering
agency. That is not so. Chevron establishes a presumption
that ambiguities are to be resolved (within the bounds of
reasonable interpretation) by the administering agency. The
implausibility of Congress's leaving a highly significant issue
unaddressed (and thus "delegating" its resolution to the
administering agency) is assuredly one of the factors to be
considered in determining whether there is ambiguity, see MC! Telecommunications Corp. v. American
Telephone & Telegraph Co., 512 U. S. 218 , 231
(1994), but once ambiguity is established the consequences of Chevron attach. 591 Drug Administration's "longstanding interpretation of the
statute," reflected in no-action notice published in the Federal
Register).

															In my view, therefore, the position that the county's action in
this case was unlawful unless permitted by the terms of an
agreement with the sheriff's department employees warrants Chevron deference if it represents the authoritative view of
the Department of Labor. The fact that it appears in a single
opinion letter signed by the Acting Administrator of the Wage and
Hour Division might not alone persuade me that it occupies that
status. But the Solicitor General of the United States, appearing
as an amicus in this action, has filed a brief, cosigned by
the Solicitor of Labor, which represents the position set forth in
the opinion letter to be the position of the Secretary of Labor.
That alone, even without existence of the opinion letter, would in
my view entitle the position to Chevron deference. What we
said in a case involving an agency's interpretation of its own
regulations applies equally, in my view, to an agency's
interpretation of its governing statute: "Petitioners complain that the Secretary's interpretation comes
to us in the form of a legal brief; but that does not, in the
circumstances of this case, make it unworthy of deference. The
Secretary's position is in no sense a 'post hoc rationalizatio[n]' advanced by an agency seeking to defend past
agency action against attack, Bowen v. Georgetown Univ.
Hospital, 488 U.
S. 204 , 212 (1988). There is simply no reason to suspect that
the interpretation does not reflect the agency's fair and
considered judgment on the matter in question." Auer v. Robbins, 519
U. S. 452 , 462 (1997). I nonetheless join the judgment of the Court because, for the
reasons set forth in Part II of its opinion, the Secretary's
position does not seem to me a reasonable interpretation of the
statute. 592 JUSTICE STEVENS, with whom JUSTICE GINSBURG and JUSTICE BREYER
join, dissenting.

															Because the disagreement between the parties concerns the scope
of an exception to a general rule, it is appropriate to begin with
a correct identification of the relevant general rule. That rule
gives all employees protected by the Fair Labor Standards Act of
1938 a statutory right to compensation for overtime work payable in
cash, whether they work in the private sector of the economy or the
public sector. 29 U. S. C. §§ 206, 207 (1994 ed. and Supp. III). In
1985, Congress enacted an exception to that general rule that
permits States and their political subdivisions to use compensatory
time instead of cash as compensation for overtime. The exception,
however, is not applicable unless the public employer first arrives
at an agreement with its employees to substitute that type of
compensation for cash. § 207(0); 29 CFR § 553.23 (1999). As I read
the statute, the employer has no right to impose compensatory
overtime payment upon its employees except in accordance with the
terms of the agreement authorizing its use.

															The Court stumbles because it treats § 207's limited and
conditional exception as though it were the relevant general rule.
The Court begins its opinion by correctly asserting that public
employers may "compensate their employees for overtime by granting
them compensatory time or 'comp time,' which entitles them to take
time off work with full pay." Ante, at 578. It is not until
it reaches the bottom of the second page, however, that the Court
acknowledges that what appeared to be the relevant general rule is
really an exception from the employees' basic right to be paid in
cash. Ante, at 579.

															In my judgment, the fact that no employer may lawfully make any
use of "comp time" without a prior agreement with the affected
employees is of critical importance in answering the question
whether a particular method of using that form 593 of noncash compensation may be imposed on those employees
without their consent. Because their consent is a condition without
which the employer cannot qualify for the exception from the
general rule, it seems clear to me that their agreement must
encompass the way in which the compensatory time may be used.

															In an effort to avoid addressing this basic point, the Court
mistakenly characterizes petitioners' central argument as turning
upon the canon expressio unius est exclusio alterius. 1
According to the Court, petitioners and the United States as amicus curiae contend that because employees are granted the
power under the Act to use their compensatory time subject solely
to the employers' ability to make employees wait a "reasonable
time" before using it, "all other methods of spending compensatory
time are precluded." Ante, at 583. The Court concludes that expressio unius does not help petitioners because the "thing
to be done" as prescribed by the statute (and because of which all
other "things" are excluded) is simply a guarantee that employees
will be allowed to make some use of compensatory time upon request,
rather than an open-ended promise that employees will be able to
choose (subject only to the "reasonable time" limitation) how to
spend it. Ibid. This description of the debate misses the primary thrust of
petitioners' position. They do not, as the Court implies, contend
that employers generally must afford employees essentially
unlimited use of accrued comp time under the statute; the point is
rather that rules regarding both the avail-

															1 It must be noted that neither petitioners' brief nor the brief
for the United States as amicus curiae actually relies upon
this canon. Indeed, the sole mention of it in either brief is in
petitioners' statement of the case, in which petitioners refer in a
single sentence to an argument made by the Court of Appeals for the
Eighth Circuit in Heaton v. Moore, 43 F. 3d 1176
(1994) (rejecting compelled-use policy absent agreement to that
effect), cert. denied sub nom. Schriro v. Heaton, 515
U. S. 1104 (1995). 594 ability and the use of comp time must be contained within an agreement. The "thing to be done" under the Act is for the
parties to come to terms. It is because they have not done so with
respect to the use of comp time here that the county may not
unilaterally force its expenditure.

															The Court is thus likewise mistaken in its insistence that under
petitioners' reading, the comp time exception "would become a
nullity" because employees could "forc[e] employers to pay cash
compensation instead of providing compensatory time" for overtime
work. Ante, at 585. Quite the contrary, employers can only
be "forced" either to abide by the arrangements to which they have
agreed, or to comply with the basic statutory requirement that
overtime compensation is payable in cash.

															Moreover, as the Court points out, ante, at 580, 584,
even absent an agreement on the way in which comp time may be used,
employers may at any time require employees to "cash out" of
accumulated comp time, thereby readily avoiding any forced payment
of comp time employees may accrue. § 207(o)(3)(B); 29 CFR §
553.26(a) (1999). Neither can it be said that Congress somehow
assumed that the right to force employees to use accumulated comp
time was to be an implied term in all comp time agreements.
Congress specifically contemplated that employees might well reach
the statutory maximum of accrued comp time, by requiring, in §
207(o)(3)(A), that once the statutory maximum is reached, employers
must compensate employees in the preferred form-cash-for every hour
over the limit.

															Finally, it is not without significance in the present case that
the Government department responsible for the statute's enforcement
shares my understanding of its meaning. Indeed, the Department of
Labor made its position clear to the county itself in response to a
direct question posed by the county before it decided-agency advice
notwithstanding-to implement its forced-use policy nonetheless. The
Department of Labor explained: 595 "[A] public employer may schedule its nonexempt employees to use
their accrued FLSA compensatory time as directed if the prior
agreement specifically provides such a provision, and the employees
have knowingly and voluntarily agreed to such provision .... "Absent such an agreement, it is our position that neither the
statute nor the regulations permit an employer to require an
employee to use accrued compensatory time." Opinion Letter from
Dept. of Labor, Wage and Hour Div. (Sept. 14, 1992), 1992 WL
845100. The Department, it should be emphasized, does not suggest that
forced-use policies are forbidden by the statute or
regulations. Rather, its judgment is simply that, in accordance
with the basic rule governing compensatory time set down by the
statutory and regulatory scheme, such policies may be pursued
solely according to the parties' agreement. Because there is
no reason to believe that the Department's opinion was anything but
thoroughly considered and consistently observed, it unquestionably
merits our respect. See Skidmore v. Swift & Co., 323 U. S.
134 , 140 (1944).2

															In the end, I do not understand why it should be any more
difficult for the parties to come to an agreement on this term of
employment than on the antecedent question whether compensatory
time may be used at all. State employers enjoy substantial
bargaining power in negotiations with their employees; by
regulation, agreements governing the availability and use of
compensatory time can be essentially as informal as the parties
wish. See 29 CFR § 553.23(c) (1999). And, as we have said,
employers retain the ability to "cash out" of accrued leave at any
time. That simple step is, after all, the method that the
Department of Labor years ago suggested the county should pursue
here, and that would

															2 I should add that I fully agree with JUSTICE BREYER'S comments
on Chevron U. S. A. Inc. v. Natural Resources
Defense Council, Inc., 467 U. S. 837 (1984). See post, at 596-597 (dissenting opinion). 596 achieve precisely the outcome the county has all along claimed
it wants.

															I respectfully dissent.

															JUSTICE BREYER, with whom JUSTICE GINSBURG joins,
dissenting.

															JUSTICE SCALIA may well be right that the position of the
Department of Labor, set forth in both brief and letter, is an
"authoritative" agency view that warrants deference under Chevron U. S. A. Inc. v. Natural Resources Defense
Council, Inc., 467 U. S. 837 (1984). Ante, at 590 (opinion concurring in part and concurring in
judgment). But I do not object to the majority's citing Skidmore v. Swift & Co., 323 U. S. 134 (1944),
instead. And I do disagree with JUSTICE SCALIA'S statement that
what he calls "Skidmore deference" is "an anachronism." Ante, at 589. Skidmore made clear that courts may pay particular
attention to the views of an expert agency where they represent
"specialized experience," 323 U. S., at 139, even if they do not
constitute an exercise of delegated lawmaking authority. The Court
held that the "rulings, interpretations and opinions of" an agency,
"while not controlling upon the courts by reason of their
authority, do constitute a body of experience and informed judgment
to which courts and litigants may properly resort for guidance." Id., at 140; see also Martin v. Occupational
Safety and Health Review Comm'n, 499 U. S. 144, 157 (1991). As
Justice Jackson wrote for the Court, those views may possess the
"power to persuade," even where they lack the "power to control." Skidmore, supra, at 140. Chevron made no relevant change. It simply focused upon
an additional, separate legal reason for deferring to certain
agency determinations, namely, that Congress had delegated to the
agency the legal authority to make those determinations. See Chevron, supra, at 843-844. And, to the extent there may be
circumstances in which Chevron-type 597 deference is inapplicable-e. g., where one has doubt that
Congress actually intended to delegate interpretive authority to
the agency (an "ambiguity" that Chevron does not
presumptively leave to agency resolution)-I believe that Skidmore nonetheless retains legal vitality. If statutes are
to serve the human purposes that called them into being, courts
will have to continue to pay particular attention in appropriate
cases to the experience-based views of expert agencies.

															I agree with JUSTICE STEVENS that, when "thoroughly considered
and consistently observed," an agency's views, particularly in a
rather technical case such as this one, "meri[t] our respect." Ante, at 595 (dissenting opinion). And, of course, I also
agree with JUSTICE STEVENS that, for the reasons he sets forth, ante, at 592-594, the Labor Department's position in this
matter is eminently reasonable, hence persuasive, whether one views
that decision through Chevron's lens, through Skidmore's, or through both.