Erie Railroad Co. v. Tompkins

Erie Railroad Co. v. Tompkins (1938) was a landmark U.S. Supreme Court case that addressed whether federal courts should apply federal or state law in certain cases. Harry Tompkins was injured by a train while walking along the tracks and sued the Erie Railroad in federal court, which applied federal common law. The Supreme Court ruled that in diversity cases (where parties are from different states), federal courts must apply state law instead. This decision emphasized the importance of state laws and reinforced the principle of federalism by ensuring that federal courts respect state legal systems in appropriate cases.