Where a state has a claim of any kind against a citizen of another state, it cannot usually prosecute that claim in its own courts, because its courts cannot get jurisdiction of a nonresident except by his voluntary appearance; and the state ought not to be compelled to submit its case to the courts of the state in which its debtor resides, because it is not consistent with the dignity of a state that it be compelled to submit itself to the jurisdiction of the courts of another independent state. Provision is therefore properly made for the trial of such cases in a federal court.

But the general rule already announced with reference to the United States, that a sovereign government should not be subject to suit, is applicable also to the sovereign states. It could not have been intended that a state government should be subject to suit by private individuals. And this principle is expressly enunciated in Amendment XI in which it is provided that "The judicial power of the United States shall not be construed to extend to any suit in law or equity commenced or prosecuted against one of the United States by citizens of another, or by citizens or subjects of any foreign state."

Even if the controversy is one arising under the constitution, laws, or treaties of the United States, and for that reason would otherwise be within the jurisdiction of the federal courts, such jurisdiction is excluded by Amendment XI if the suit is by private individuals or corporations against a state, and the same reasoning applies to a suit against a state by its own citizens, for, although this class of cases is not expressly covered by the Eleventh Amendment, it is excluded from the jurisdiction of the federal courts by the general rule that a sovereign state cannot be sued except by its own consent (Hans v. Louisiana). Whether the citizens of a state may sue the state in its own courts will depend entirely on the laws of the state, and such authority has in some cases, although not generally, been granted. The conclusion to be drawn is that the jurisdiction of the federal courts does not extend to suits against a state, no matter what be the nature of the subject-matter, unless the suit be by another state of the Union or by a foreign state, or by the United States.