The Supremacy Clause (Article VI, Clause 2) establishes that the Constitution, federal laws, and treaties are "the supreme Law of the Land," binding all state judges. When federal law and state law conflict, federal law prevails. Courts determine whether preemption applies by looking for: (1) express preemption, where Congress explicitly said so; (2) field preemption, where Congress regulated so thoroughly that no room remains for state action; or (3) conflict preemption, where compliance with both laws is impossible, or state law stands as an obstacle to federal purposes. In the Kalshi prediction market disputes, the question is whether the Commodity Exchange Act preempts state gambling licensing. Courts reached contradictory answers in 2025-2026, creating a circuit split that may require Supreme Court resolution.