Federal question jurisdiction exists when the case arises under the Constitution, laws, or treaties of the United States. The “arises under” requirement normally is met when a right created by federal law is a basic part of the plaintiff’s case. There is no amount-in-controversy requirement for federal question jurisdiction. Diversity jurisdiction and federal question jurisdiction are forms of subject-matter jurisdiction. Even if one of the two forms exists, a federal district court must also have in personam jurisdiction in order to render a decision that is binding on the parties. As noted earlier in the chapter, the analysis of in personam jurisdiction issues in the federal court system is essentially the same as in the state court systems.
Further limiting the plaintiff’s choice of federal district courts are the federal system’s complex venue requirements, which are beyond the scope of this text. The federal district courts have exclusive jurisdiction over some matters. Patent cases, for example, must be litigated in the federal system. Often, however, federal district courts have concurrent jurisdiction with state courts—meaning that both state and federal courts have jurisdiction over the case. For example, a plaintiff might assert state court in personam jurisdiction over an out-of-state defendant or might sue in a federal district court under that court’s diversity jurisdiction.
A state court, moreover, may sometimes decide cases involving federal questions.