In the United States Supreme Court case of The United States v. Edward Simon, the court was asked to decide whether a state law could be used to prevent federal officers from executing their duties. At issue was an 1848 Louisiana statute that prohibited any person from entering or remaining on public land without permission and imposed fines for violations of this law. The government argued that this statute interfered with its authority under the Constitution to manage public lands within its borders and thus violated Article VI, Clause 2 (the Supremacy Clause). After considering both sides’ arguments, the court held that while states have certain powers over their own lands, they cannot interfere with Congress’s power over national property by passing laws which would impede federal officers in carrying out their duties. Therefore, it concluded that Louisiana's statute was unconstitutional because it attempted to limit Congress' power over federally owned land and thus violated the Supremacy Clause of Article VI.

In the case of United States v. Edward Simon, the Supreme Court was asked to decide whether a person who had been convicted in a state court for an offense that was also punishable under federal law could be tried again by the federal government for that same offense. The majority opinion held that such double jeopardy did not exist and thus allowed Simon's conviction to stand. However, Justice McLean dissented from this decision on two grounds: firstly, he argued that since both state and federal governments were created by the Constitution they should have concurrent jurisdiction over criminal matters; secondly, he contended that allowing multiple prosecutions would violate fundamental principles of justice as it would subject individuals to oppressive punishments or even death if found guilty more than once for one crime. Ultimately, Justice McLean concluded his dissent with a call for Congress to pass legislation protecting citizens from being subjected to double jeopardy in order to ensure fairness and justice within our legal system.