Article III, Section 2, Clause 2:
In all Cases affecting Ambassadors, other public Ministers and Consuls, and those in which a State shall be a Party, the supreme Court shall have original Jurisdiction. In all the other Cases before mentioned, the Supreme Court shall have appellate Jurisdiction, both as to Law and Fact, with such Exceptions, and under such Regulations as the Congress shall make.
The Constitution established a system of government in which total power, sovereignty, was not unequivocally lodged in one level of government. In Chief Justice Marshall's words, "our complex system [presents] the rare and difficult scheme of one general government, whose actions extend over the whole, but which possesses only certain enumerated powers, and of numerous state governments, which retain and exercise all powers not delegated to the Union. . . ." Naturally, in such a system, "contests respecting power must arise." 1 Contests respecting power may frequently arise in a federal system with dual structures of courts exercising concurrent jurisdiction in a number of classes of cases. Too, the possibilities of frictions grow out of the facts that one set of courts may interfere directly or indirectly with the other through injunctive and declaratory processes, through the use of habeas corpus and removal to release persons from the custody of the other set, and through the refusal by state courts to be bound by decisions of the United States Supreme Court. The relations between federal and state courts are governed in part by constitutional law, with respect, say, to state court interference with federal courts and state court refusal to comply with the judgments of federal tribunals; in part by statutes, with respect to the federal law generally enjoining federal court interference with pending state court proceedings; and in part by self-imposed rules of comity and restraint, such as the abstention doctrine, all applied to avoid unseemly conflicts, which, however, have at times occurred.
Subject to congressional provision to the contrary, state courts have concurrent jurisdiction over all the classes of cases and controversies enumerated in Article III, except suits between states, those to which the United States is a party, those to which a foreign state is a party, and those within the traditional admiralty jurisdiction. 2 Even within this last category, however, state courts, though unable to prejudice the harmonious operation and uniformity of general maritime law, 3 have concurrent jurisdiction over cases that occur within the maritime jurisdiction when such litigation assumes the form of a suit at common law. 4 Review of state court decisions by the United States Supreme Court is intended to protect the federal interest and promote uniformity of law and decision relating to the federal interest. 5 The first category of conflict surfaces here. The second broader category arises from the fact that state interests, actions, and wishes, all of which may at times be effectuated through state courts, are variously subject to restraint by federal courts. Although the possibility always existed, 6 it became much more significant and likely when, in the wake of the Civil War, Congress bestowed general federal question jurisdiction on the federal courts, 7 enacted a series of civil rights statutes and conferred jurisdiction on the federal courts to enforce them, 8 and most important proposed and saw to the ratification of the three constitutional amendments, especially the Fourteenth, which made an ever-increasing number of state actions subject to federal scrutiny. 9