Intergovernmental immunity is a doctrine derived from the Supremacy Clause (Article VI) holding that states may not impose discriminatory burdens on the federal government or directly regulate how federal agencies and officers carry out federal law. The doctrine originated in McCulloch v. Maryland (1819), where the Supreme Court struck down a Maryland tax on the Bank of the United States. Courts apply it to block state laws that single out federal actors for rules not applied equally to state actors. In the immigration enforcement context, courts have used intergovernmental immunity to strike down state laws requiring ICE agents to show ID or remove masks, reasoning that such laws directly regulate the federal government and are void regardless of whether the regulated activities are essential to federal functions.