Below is a comprehensive compilation of U.S. federal laws historically and currently aimed at combating communism and subversive activities, particularly within institutions such as government, labor unions, education, and other positions of influence. This list draws from historical anti-communist legislation primarily from the First and Second Red Scares (1917–1920 and 1940s–1950s), as well as remnants still on the books. Many provisions have been limited, repealed, or declared unconstitutional by the Supreme Court on First Amendment grounds (e.g., requiring specific intent for advocacy of overthrow rather than mere belief). Enforcement today is rare and typically requires evidence of criminal acts like espionage or incitement to violence, not ideological affiliation alone.

The list is organized chronologically and includes:

• Full Name and Citation: Legal reference.
• Key Provisions: Focus on those enabling prosecution, registration, removal from positions, or restrictions in institutions.
• Application to Institutions: How it targets roles in government, unions, etc.
• Current Status (as of September 2025): Enforceability, amendments, or court rulings.

Law	Citation	Key Provisions	Application to Institutions	Current Status (as of September 2025)
Voorhis Act (Foreign Agents Registration Act Amendments)	18 U.S.C. § 2386 (originally 54 Stat. 1138, 1940)	Requires organizations advocating overthrow of the U.S. government by force or violence (including communist groups) to register with the Attorney General and disclose foreign ties; failure is punishable by up to 5 years imprisonment and $10,000 fine.	Targets subversive groups infiltrating unions, political organizations, or educational institutions; used to monitor communist fronts.	Still in effect as part of FARA; enforced for foreign agents but rarely for domestic communism without foreign links. Upheld in cases like U.S. v. Dennis (1951).
Alien Registration Act (Smith Act)	18 U.S.C. § 2385	Criminalizes teaching, printing, or advocating overthrow of the U.S. government by force/violence; prohibits membership in groups plotting such overthrow; penalties up to 20 years imprisonment and $20,000 fine.	Used to prosecute Communist Party leaders and remove them from federal employment or union roles via loyalty oaths.	Active but narrowed by Yates v. U.S. (1957) (requires incitement to imminent lawless action) and Scales v. U.S. (1961) (active membership with intent only); last major use in 1950s, but applicable to modern sedition cases.
Taft-Hartley Act (Labor Management Relations Act), Section 9(h)	29 U.S.C. § 159(h) (originally 61 Stat. 136, 1947; repealed 1959)	Required union officers to sign affidavits disavowing communist affiliation; non-compliant unions lost NLRB protections.	Barred communists from union leadership, affecting labor institutions.	Repealed by Labor-Management Reporting and Disclosure Act (1959); historical only. Upheld initially in American Communications Ass’n v. Douds (1950).
Executive Order 9835 (Employee Loyalty Program)	5 C.F.R. § 731.101 et seq. (1947; revoked 1953)	Established loyalty review boards to investigate federal employees for “totalitarian, fascist, communist, or subversive” affiliations; grounds for dismissal included membership in listed subversive groups.	Led to purges of ~5,000 federal workers suspected of subversion in government institutions.	Revoked by Executive Order 10450 (1953); influenced modern security clearance processes but no longer directly enforceable.
McCarran Internal Security Act (Subversive Activities Control Act of 1950)	50 U.S.C. §§ 781–798 (originally 64 Stat. 987, 1950)	Requires registration of “Communist-action” (foreign-controlled) and “Communist-front” organizations; bars members from federal jobs, passports, and citizenship; authorizes emergency detention of subversives; prohibits sharing classified info with communists.	Targets infiltration in government, defense, and unions; created Subversive Activities Control Board to investigate and remove from sensitive positions.	Partially repealed (e.g., detention in 1971 Non-Detention Act; Board abolished 1972); registration invalidated in Albertson v. SACB (1965) on self-incrimination; passport ban struck in Aptheker v. Sec’y of State (1964); employment ban in U.S. v. Robel (1967). Remnants (e.g., §797 on military regulations) still used.
Immigration and Nationality Act (McCarran-Walter Act)	8 U.S.C. §§ 1182(a)(3)(D), 1227(a)(4)(B) (1952)	Makes communist affiliation grounds for inadmissibility/deportation; bars naturalization for current/former party members unless they prove non-advocacy of force.	Prevents subversives from entering or holding influential roles in U.S. institutions; used for deportation from academia/government.	Active; Section 241(a)(6)(C) invoked in 2025 case against Mahmoud Khalil for alleged communist ties. Upheld in Galvan v. Press (1954) but challenged on due process.
Labor-Management Reporting and Disclosure Act (Landrum-Griffin Act), Section 504	29 U.S.C. § 504 (1959)	Prohibits convicted communists or those advocating overthrow from holding union office for 5 years post-conviction; penalties up to 10 years imprisonment and $10,000 fine.	Removes subversives from labor union leadership positions.	Active but limited by Brown v. U.S. (1965) requiring specific intent; rarely enforced today.
Communist Control Act of 1954	50 U.S.C. §§ 841–844 (68 Stat. 775, 1954)	Outlaws the Communist Party as a conspiracy to overthrow government; criminalizes membership/support (up to 5 years/$10,000); strips party of legal rights (e.g., no ballot access, suits); defines “communist-infiltrated organizations” for removal of leaders.	Bars communists from unions, government, and elections; targets institutional influence.	Still on books, never repealed; unused since 1950s due to constitutionality issues (e.g., bills of attainder); ruled unconstitutional in Blawis v. Bolin (1973) for ballot bans; dormant but cited in 2025 discussions on anti-communism.
Executive Order 10450 (Security Requirements for Government Employment)	5 C.F.R. Part 731 (1953; amended)	Mandates loyalty checks for federal employees; denies clearances for subversive associations, including communism; allows removal for “criminal, infamous, dishonest, immoral, or notoriously disgraceful conduct.”	Applies to all federal institutions; basis for modern background checks revoking access for subversives.	Active and amended (e.g., by EO 12968 in 1995); focuses on conduct over ideology; used in security clearances.
18 U.S.C. Chapter 115 (Treason, Sedition, and Subversive Activities)	18 U.S.C. §§ 2381–2391 (various, consolidated 1948)	Covers treason (§2381, death/imprisonment), seditious conspiracy (§2384, up to 20 years), advocating overthrow (§2385, Smith Act), and rebellion (§2383); broad anti-subversion framework.	Prosecutes subversives in any institution plotting against government.	Fully active; used in modern cases (e.g., January 6, 2021 prosecutions under §2384); no major changes in 2025.