The Prize Cases

The Court upheld President Lincoln's blockade of southern ports as a lawful response to insurrection, recognizing broad executive war powers.

Overview

Union ships seized vessels trading with the Confederacy under Lincoln's 1861 blockade proclamation, issued without a congressional declaration of war. Shipowners argued the seizures were unlawful because Congress had not authorized war. Justice Grier, for a 5-4 majority, held that a state of civil war existed as a matter of fact, and that the President as commander in chief could respond to sudden attack and insurrection without waiting for Congress. The decision recognized that the executive may act militarily when the nation is attacked, an early pillar of modern executive power doctrine, while leaving the boundaries of that power contested.