Facing a strike by steelworkers during the Korean War, Truman invoked his powers as commander in chief and seized the steel mills. He claimed that such seizure for the government was necessary as an emergency measure during the war. The owners of the steel mills sued in court for an injunction and ultimately prevailed. The U.S. Supreme Court ruled 6 to 3 in Youngstown Sheet and Tube Co. v. Sawyer (1952) that the actions of the executive branch infringed upon the fundamental principle of separation of powers. The Court reasoned that Truman’s actions invaded the province of the legislative branch, as the seizure of the steel mills could only be done (if at all) by an act of Congress.

Interestingly, the attorney for the steel mills was attorney John W. Davis, the 1924 Republican Party presidential nominee who lost to Calvin Coolidge.