The Supreme Court overturned statutes requiring loyalty oaths, viewing them as unconstitutional ex post facto laws and bills of attainder.

Justice Stephen J. FieldField, Stephen J.;Cummings v. Missouri[Cummings v. Missouri] wrote the opinions for both Cummings and its companion case, Ex parte Garland, which were decided by 5-4 votes with Justice Samuel F. Miller dissenting. Cummings involved a Missouri law that retroactively imposed loyalty oaths requiring people in various jobs to swear that they had not aided or sympathized with the southern cause during the Civil War. Garland dealt with a federal law requiring attorneys practicing in federal court to swear that they had not supported the Confederacy.[case]Cummings v. Missouri[Cummings v. Missouri]Loyalty oaths;Cummings v. Missouri[Cummings v. Missouri]

One of Justice Stephen J. Field’s principal objections to loyalty oath statutes was that they constituted a form of ex post facto law.

(Library of Congress)

Field noted that, although these statutes did not impose fines or imprisonment, they were punitive because they banned those who could not take oaths honestly from practicing their professions. Sections 9 and 10 of Article I of the U.S. Constitution ban bills of attainder and ex post facto laws at the state and federal level. Field found the statutes in Cummings and Garland to be ex post facto retroactive legislation (laws that criminalized acts considered legal when committed) and bills of attainder because they imposed punishment without trial to a designated group of individuals. Miller, in dissent, argued that the statutes were not imposing punishment and therefore could not be either bills of attainder or ex post facto laws. This decision, never repudiated by the Supreme Court, was used in United States v. Brown[case]Brown, United States v.[Brown, United States v.] (1965) to void a federal law that banned former communists from serving as labor union officials.

Bill of attainder

Dennis v. United States

Ex post facto laws

Scales v. United States

Yates v. United States