United States v. Palmer was a Supreme Court case decided in 1818. The case involved a dispute between the United States and John Palmer, a merchant from New York. Palmer had been accused of violating the Neutrality Act of 1794 by trading with the French West Indies. The United States argued that Palmer had violated the Neutrality Act by trading with the French West Indies, and sought to have Palmer convicted and fined. The Supreme Court ultimately ruled in favor of the United States, finding that Palmer had violated the Neutrality Act. The Court held that the Neutrality Act was a valid exercise of Congress’s power to regulate foreign commerce, and that Palmer’s actions constituted a violation of the Act. The Court also held that the United States had the right to prosecute Palmer for his violation of the Act. The decision in United States v. Palmer established the principle that Congress has the power to regulate foreign commerce, and that individuals who violate such regulations can be prosecuted by the United States. The case also established the principle that individuals who violate the Neutrality Act can be held liable for their actions.

In the dissenting opinion of United States v. Palmer, Justice Field argued that Congress had no authority to pass a law criminalizing the possession of firearms by an individual who was not part of any organized militia or military force. He argued that such a law would be in violation of the Second Amendment which states “A well regulated Militia, being necessary to the security of a free State, the right of people to keep and bear Arms shall not be infringed”. In his opinion he stated that this amendment was intended as protection for citizens against oppressive government action and should only apply when individuals are acting under some form or organization sanctioned by their state governments. Furthermore, he believed it was unconstitutional for Congress to use its power over interstate commerce as justification for passing such legislation since there is nothing in either Article I Section 8 or any other clause granting them this power. As such Justice Field concluded that Congress did not have authority to pass laws regulating firearm possession outside those related directly with militias and therefore found United States v Palmer unconstitutional on these grounds