In Locke v. The United States, the Supreme Court ruled that a federal law which authorized the President to issue letters of marque and reprisal was unconstitutional. This case arose from an incident in 1812 when Thomas Locke, a privateer commissioned by President James Madison under this law, captured two Spanish vessels off the coast of Florida. Spain sued for damages in U.S. district court on behalf of its citizens who owned one of the ships seized by Locke's crew; however, it argued that Congress had no authority to pass such legislation because it violated Article I Section 8 Clause 11 of the Constitution which grants only Congress power "to declare war." The Supreme Court agreed with Spain and held that while Congress has broad powers over foreign affairs including declaring war and making treaties with other nations, they do not extend so far as authorizing individuals or groups to engage in acts hostile towards another nation without Congressional approval first being granted through formal declaration or treaty provisions allowing such action against them.

Justice Johnson delivered the dissenting opinion in Locke v. United States, arguing that Congress had exceeded its authority by passing a law which allowed for the seizure of property without due process of law. He argued that this was an unconstitutional act as it violated both Article III and Amendment V of the Constitution, which guarantee citizens certain rights to their property and require due process before any such seizures can take place. Furthermore, he argued that Congress should not be able to pass laws which are contrary to those established by the Supreme Court or other courts within their jurisdiction. In conclusion, Justice Johnson believed that Congress had overstepped its bounds in passing this particular legislation and thus it should be declared unconstitutional.