35. The power of Congress, expressly delegated to it, “to define and punish piracies and felonies committed on the high seas, and offenses against the law of nations,” is not exclusive. The States are not prohibited from legislating on the subject. Offenses committed within the jurisdiction of a State are punishable by State laws. Such offenses are punishable by common law. If there is no act of Congress covering the offense, then the United States has not assumed jurisdiction. But absence of a specific mention or definition of the offense does not invalidate a claim of jurisdiction when the result of the offense is piracy. Piracy is robbery committed within the jurisdiction of the admiralty,[84] but an offense that effects piracy, though not technically robbery, is piracy.[85] As piracy is an offence against the law of nations, and not strictly against domestic municipal law, it falls within the jurisdiction of the admiralty—a jurisdiction over which the judicial power of the United States is expressly extended by the Constitution.[86] This jurisdiction is not exclusive as provided for by the Constitution. Practically, however, the States do not legislate on the subject, unless it be to provide for the execution of their police power over their own waters. 36. The “admiralty jurisdiction” of the United States is co-extensive with its authority over or on waters, fresh or salt, including the high seas, the Great Lakes, and rivers and streams commerce over which it has power to regulate. Thus this jurisdiction is over the American ship wherever it may be. “Offenses committed on vessels belonging to citizens of the United States, within their admiralty jurisdiction (‘that is within navigable waters’) though out of the territorial limits of the United States, may be judicially considered when the vessel and parties are brought within their territorial jurisdiction.”[87]