Subject-matter jurisdiction
Subject-matter jurisdiction, also called jurisdiction ratione materiae, is a legal doctrine holding that a court can only hear and decide cases of a particular type (i.e., cases relating to a specific subject matter). The subject matter jurisdiction of a court may be described as either limited jurisdiction, meaning it is able to hear only certain types of cases, or general jurisdiction, meaning it is presumed able to hear and decide all types of cases. For instance, a bankruptcy court only has the authority to hear bankruptcy cases. Subject-matter jurisdiction must be distinguished from personal jurisdiction, which is the power of a court to render a judgment against a particular defendant, and territorial jurisdiction, which is the power of the court to render a judgment concerning events that have occurred within a well-defined territory. Unlike personal or territorial jurisdiction, lack of subject-matter jurisdiction cannot be waived. A judgment from a court that did not have subject-matter jurisdiction is forever a nullity. To decide a case, a court must have a combination of subject (subjectam) and either personal (personam) or territorial (locum) jurisdiction. Subject-matter jurisdiction, personal or territorial jurisdiction, and adequate notice are the three most fundamental constitutional requirements for a valid judgment. United States

General jurisdiction vs. limited jurisdiction
The subject matter jurisdiction of state courts and federal courts in the United States often overlaps. Many types of cases can be heard either in state or federal courts. However, the federal courts are all courts of limited jurisdiction, while most states have both courts of limited jurisdiction and courts of general jurisdiction. State courts
Many state court systems are divided into divisions such as criminal, civil law, family, and probate. A court within any one of those divisions would lack subject-matter jurisdiction to hear a case regarding matters falling outside the scope of the type of cases assigned to it. Most U.S. state court systems, however, include a superior court that has "general" jurisdiction; that is, it is competent to hear any case over which no other state court has exclusive jurisdiction. Because the percentage of claims over which the United States federal courts have exclusive jurisdiction, such as copyright disputes, patent disputes, and United States bankruptcy court disputes, makes up a small percentage of overall cases, state courts have the authority to hear the vast majority of cases. U.S. federal courts
Subject-matter jurisdiction is significantly more limited in United States federal courts. The maximal constitutional bounds of federal courts' subject-matter jurisdiction are defined by Article III Section 2 of the U.S. Constitution. Federal courts' actual subject-matter jurisdiction derives from Congressional enabling statutes, such as  and . The United States Congress has not extended federal courts' subject-matter jurisdiction to its constitutional limits. For example, the amount-in-controversy requirement for diversity jurisdiction is based on , not a constitutional restriction. Moreover, Congress could constitutionally overrule the complete diversity rule in diversity cases, which predominantly holds that each plaintiff must be a citizen of a different state than each defendant. The two primary categories of federal subject-matter jurisdiction in civil cases are federal question jurisdiction and diversity jurisdiction. The enabling statute for federal question jurisdiction, , provides that the district courts have original jurisdiction in all civil actions arising under the Constitution, laws, or treaties of the United States. As mentioned before, this jurisdiction by default is not exclusive; states can also hear claims based on federal law. The enabling statute for diversity jurisdiction, 28 U.S.C. § 1332, grants the district courts jurisdiction in a most types of actions, so long as they meet two basic conditions:

Complete diversity requirement. No defendant is a citizen of the same state as any plaintiff. Amount in controversy requirement. The matter in controversy exceeds $75,000. Federal courts separately may exert diversity jurisdiction over class action cases so long as they meet the jurisdictional requirements of the Class Action Fairness Act of 2005, namely:

Minimal diversity. At least one member of the class is a citizen of a different state than at least one defendant. Amount in controversy requirement. The matter in controversy exceeds $5 million. Federal courts also have removal jurisdiction, which is the authority to try cases removed by defendants from state courts. The contours of removal jurisdiction are almost identical to those of original jurisdiction. According to Rule 12(b)(1) of the Federal Rules of Civil Procedure, a federal court has the authority to dismiss a case for lack of subject-matter jurisdiction upon motion of a party or sua sponte, upon its own initiative. In federal criminal cases (offenses against the laws of the United States), the federal district courts of the United States have subject matter jurisdiction granted under . See also
 General jurisdiction (Ordinary court)
 Limited jurisdiction (Specialized court)

References

Civil procedure
American legal terminology
Jurisdiction