A federal court having assumed jurisdiction over a person or piece of property, the state authorities are excluded from any interference therewith or from in any way assuming jurisdiction therein. This principle was violated by the authorities of the State of Wisconsin in the case of Ableman v. Booth1 in annulling the proceedings of a commissioner of the United States and discharging a prisoner who had been committed by the commissioner for an offense against a federal law. The Supreme Court of the United States declared the impropriety of these actions in the following language: "The supremacy of the state courts over the courts of the United States, in cases coming under the Constitution and laws of the United States is now for the first time asserted and acted upon in the supreme court of a State." Protesting against this action, the opinion declares: "...We do not question the authority of state court, or judge, who is authorized by the laws of the State to issue the writ of habeas corpus, to issue it in any case where the party is imprisoned within its territorial limits, provided it does not appear, when the application is made, that the .person imprisoned is in custody under the authority of the United States. The court or judge has a right to inquire, in this mode of proceeding, for what cause and by what authority the prisoner is confined within the territorial limits of the state sovereignty. But, after the return is made, and the state judge or court is judicially apprised that the party is in custody under the authority of the United States, they can proceed no further."

That a state court has no power to issue a mandamus or writ of certiorari to a federal officer is not questioned.2

1 21 How. 506.

M'Clung v. Silliman. 6 Wh. 598: 5 L. ed. 340: Kendall v. U. S.. 12 Pet. 624; 9 L. ed. 1181; U. S. v. Schurz (102 U. S. 378; 20 L. ed. 167).

The inability of the state courts by injunction or otherwise to control proceedings in federal courts is declared in Weber v. Lee Co.,3 United,States v. Keokuk,4 and Supervisors v. Durant.5 This inability arises not so much from the supremacy of the federal courts as because the state and federal judicial systems are independent of one another. In Weber v. Lee Co. the court say: "State courts cannot enjoin the process of proceedings in the circuit [federal] courts; not on account of any paramount jurisdiction in the latter, but because they are entirely independent in their sphere of action." The same reason is given in United States v. Keokuk.