The Union itself may be invoked in legal proceedings, and in this case it would be alike contrary to the customs of all nations and to common sense to appeal to a tribunal representing any other sovereignty than its own; the Federal courts, therefore, take cognizance of these affairs. When two parties belonging to two different States are engaged in a suit, the case cannot with propriety be brought before a court of either State. The surest expedient is to select a tribunal like that of the Union, which can excite the suspicions of neither party, and which offers the most natural as well as the most certain remedy. When the two parties are not private individuals, but States, an important political consideration is added to the same motive of equity. The quality of the parties in this case gives a national importance to all their disputes; and the most trifling litigation of the States may be said to involve the peace of the whole Union. *f f [ The Constitution also says that the Federal courts shall decide “controversies between a State and the citizens of another State.” And here a most important question of a constitutional nature arose, which was, whether the jurisdiction given by the Constitution in cases in which a State is a party extended to suits brought against a State as well as by it, or was exclusively confined to the latter. The question was most elaborately considered in the case of Chisholm v. Georgia, and was decided by the majority of the Supreme Court in the affirmative. The decision created general alarm among the States, and an amendment was proposed and ratified by which the power was entirely taken away, so far as it regards suits brought against a State. See Story’s “Commentaries,” p. 624, or in the large edition Section 1677.] The nature of the cause frequently prescribes the rule of competency. Thus all the questions which concern maritime commerce evidently fall under the cognizance of the Federal tribunals. *g Almost all these questions are connected with the interpretation of the law of nations, and in this respect they essentially interest the Union in relation to foreign powers. Moreover, as the sea is not included within the limits of any peculiar jurisdiction, the national courts can only hear causes which originate in maritime affairs. g [ As for instance, all cases of piracy.] The Constitution comprises under one head almost all the cases which by their very nature come within the limits of the Federal courts. The rule which it lays down is simple, but pregnant with an entire system of ideas, and with a vast multitude of facts. It declares that the judicial power of the Supreme Court shall extend to all cases in law and equity arising under the laws of the United States. Two examples will put the intention of the legislator in the clearest light: