The Supreme Court case United States vs Leon established the "good faith" exception to the exclusionary rule. Police in Burbank, California received a tip about illegal drug sales and obtained a search warrant, which was later found to be invalid. However, the Court ruled the evidence could still be used because the police were acting in good faith that the warrant was valid.
In McCulloch vs Maryland, the Supreme Court ruled Maryland could not tax the national bank established by Congress. The Court found the bank was a valid exercise of federal power, so Maryland's tax on the bank was unconstitutional as it interfered with federal law. The ruling established federal law supersedes any state laws that impede federal powers.
