In the United States vs. Isaac T. Preston, Attorney General of Louisiana, the Supreme Court heard a case concerning whether or not Congress had authority to pass legislation that would regulate commerce between states and foreign nations. The appellant argued that Congress did have such power under Article I Section 8 of the Constitution which grants them authority to "regulate Commerce with foreign Nations, and among several States." The appellee countered by arguing that this was an issue for individual state legislatures to decide as it fell outside of Congressional jurisdiction. Ultimately, the Supreme Court sided with the appellant in a 6-1 decision ruling that Congress does indeed have constitutional authority over interstate commerce and can therefore pass laws regulating it accordingly. This landmark decision established federal supremacy over state law when it comes to matters related to interstate trade thus setting an important precedent for future cases involving similar issues.

In the case of The United States vs. Isaac T. Preston, Attorney General of Louisiana, the Supreme Court was asked to decide whether a state could tax federal property within its borders. The majority opinion held that states do not have this power and cannot impose taxes on federal property without permission from Congress. However, Justice Story dissented from this ruling and argued that states should be able to exercise their sovereign powers over all lands within their boundaries regardless of ownership by the Federal Government or any other entity. He reasoned that if a state is unable to tax land owned by another government it would be deprived of an important source of revenue necessary for public services such as education and infrastructure development which are essential for maintaining order in society. Furthermore, he noted that allowing taxation on federal properties would help ensure uniformity across different jurisdictions since each state can set its own rules regarding taxation rather than having them dictated by Congress or some other external authority.