The federal courts can lend their aid to carry into effect a right arising wholly from the statute of a State, even if it affect maritime interests and must be enforced, if at all, through an admiralty court. Admiralty suits, it is true, can only be brought in the courts of the United States, but that is the very reason why, if such a suit gives the only remedy, jurisdiction of it should be entertained in the only sovereignty competent to give relief.[Footnote: The Lottawanna, 21 Wallace's Reports, 558, 580.] There are many civil cases which can be brought, at the option of the plaintiff, either in a court of the United States or in a State court. Some of these, if brought in a State court, the defendant can, at his option, allow to remain there or remove for trial into the Circuit Court of the United States. Criminal prosecutions by a State may also be removed, under certain conditions, to the Circuit Court of the United States, when the defense is one arising under the laws of the United States. In any cause tried in a State court, if the decision turns on a claim of right, set up under the Constitution, laws or treaties of the United States, and is against its validity, the losing party, if unable to secure its reversal by appeal to a higher court of the State, can ask such relief from the Supreme Court of the United States. It will be observed that it is the losing party only who has this remedy. If the State court decides, however erroneously, that the claim of a federal right is well grounded, this is conclusive as respects the controversy in that suit. If all State courts in which the validity of an unconstitutional Act of Congress was contested should uphold it, the courts of the United States would be powerless to right the wrong, unless they were called upon to enforce the statute in some suit brought before them for original trial.