The United States Supreme Court case of The United States v. Charles Fossatt involved a dispute over the ownership of certain lands in California. At issue was whether or not the land had been granted to Fossatt by an act of Congress, and if so, whether it could be sold without his consent. The court held that although Fossatt had received title to the land from an act of Congress, he did not have absolute power over it as he was subject to restrictions imposed by law. Furthermore, any sale made without his consent would be voidable at his option and thus invalid under state law. Ultimately, this decision affirmed that while individuals may receive grants from acts of Congress they are still bound by applicable laws when disposing such property rights.

In the case of United States v. Charles Fossatt, the Supreme Court was tasked with deciding whether or not a person could be convicted for an act that had been declared legal by Congress. The majority opinion held that Fossatt should be found guilty because he committed his crime before Congress passed its law making it legal. However, in dissent Justice Curtis argued that this decision would create a dangerous precedent and violate due process rights as established by the Fifth Amendment to the Constitution which states no one shall “be deprived of life, liberty or property without due process of law”. He argued that if someone is charged with committing an act after it has become illegal but before they have received notice of such illegality then they cannot be punished for their actions since there was no way for them to know what laws were in effect at any given time and thus could not comply with them accordingly. Therefore, according to Justice Curtis' dissenting opinion Fossatt should have been acquitted on all charges as he did nothing wrong under existing laws when he committed his alleged crimes