The McCarran Internal Security Act of 1950 was a sweeping Cold War statute that required Communist organizations to register with the federal government, cut their members off from passports and defense jobs, authorized the emergency detention of suspected saboteurs, and tightened immigration rules against past or present Communist affiliation. Congress passed it over President Truman’s veto in September 1950. Most of what it set up was later struck down by the Supreme Court or repealed by Congress, but two narrow criminal provisions dealing with classified information and defense-facility security remain enforceable federal law.
How the Law Was Enacted
President Truman vetoed the bill on September 22, 1950. In his veto message he reported that the Departments of Justice, Defense, State, and the CIA all warned him the legislation would “seriously damage the security and the intelligence operations for which they are responsible,” and he argued it would “put the Government of the United States in the thought control business.”1The American Presidency Project. Veto of the Internal Security Bill
Congress overrode him the same day. The Korean War had begun months earlier, and the political climate left little room for opposition. The Act became law on September 23, 1950.
Registration of Communist Organizations
The core of the Act was a mandatory registration system, originally codified at 50 U.S.C. §§ 786–787. Any organization the government classified as a “Communist-action” or “Communist-front” group had to register with the U.S. Attorney General, list its officers and members, and file detailed annual reports of its finances and contributors.2Office of the Law Revision Counsel. 50 USC Chapter 23 – Internal Security
A “Communist-action” organization was one the government said operated under the control of a foreign Communist government. A “Communist-front” was one substantially directed or controlled by a Communist-action group, even if it had a broader public mission. Both categories carried the same registration obligations, though individual members of Communist-action groups faced additional personal restrictions.
Failure to register was a crime, and each day of noncompliance counted as a separate offense. In practice, no organization ever voluntarily registered. The Communist Party fought the requirement through years of litigation until the courts dismantled the framework.
What Membership Cost a Person
Once an organization was registered, its members lost significant rights automatically. They could not obtain or use a U.S. passport. They could not work for the federal government or hold any job at a defense facility. These consequences applied regardless of what a person actually did within the group.
The Act also required registered organizations to label their public communications. Mailed or distributed publications had to carry a printed notice reading “Disseminated by [organization name], a Communist organization,” and broadcasts sponsored by such groups needed a spoken equivalent.3U.S. Statutes at Large. Internal Security Act of 1950
The Subversive Activities Control Board
The Act created the Subversive Activities Control Board, an independent five-member federal body appointed by the President and confirmed by the Senate for five-year terms.4Richard Nixon Library and Museum. FG 220 Subversive Activities Control Board The Attorney General would petition the Board to hold hearings on whether a particular organization qualified as Communist-action or Communist-front. The targeted group could present evidence and cross-examine witnesses, giving the proceedings a trial-like structure, but the government did not have to prove any crime had been committed to impose the registration regime and everything that followed from it.
Emergency Detention
Title II of the Act, the Emergency Detention Act, was its most alarming feature. It authorized the President to declare an “internal security emergency” in the event of invasion, a congressional declaration of war, or an insurrection in aid of a foreign enemy. Once declared, the Attorney General could apprehend and detain anyone the government had “reasonable ground to believe” would probably engage in espionage or sabotage.5Congressional Research Service. Detention of U.S. Citizens This was preventive detention: the government needed a prediction about future conduct, not evidence of a past crime.
A nine-member Detention Review Board was supposed to hear appeals, with hearings required within thirty days of a petition.2Office of the Law Revision Counsel. 50 USC Chapter 23 – Internal Security The federal government went so far as to designate physical detention sites around the country to be kept in readiness, and the parallels to the World War II internment of Japanese Americans were obvious.
Congress repealed Title II in 1971 through the Non-Detention Act, replacing it with one sentence: “No citizen shall be imprisoned or otherwise detained by the United States except pursuant to an Act of Congress.”6Office of the Law Revision Counsel. 18 U.S. Code 4001 – Limitation on Detention; Control of Prisons
Immigration and Citizenship Consequences
The Act reshaped immigration law. Federal authorities could exclude or deport any noncitizen who was or had ever been a member of a Communist or other totalitarian party. Even long-lapsed membership from decades earlier in a foreign country created a permanent bar to entry.
Naturalization tightened too. Applicants had to show they had not belonged to a prohibited organization for a substantial period before applying. If a new citizen joined such an organization within five years of naturalization, the government could treat that as evidence the person had never truly been loyal and move to revoke citizenship.7Office of the Law Revision Counsel. 8 USC 1451 – Revocation of Naturalization
The Attorney General also had six months after issuing a deportation order to remove a noncitizen, and could detain the person, release them on conditional parole, or require a bond during that period.3U.S. Statutes at Large. Internal Security Act of 1950
How the Courts Dismantled It
The Act faced a long series of constitutional challenges, and the government lost almost every significant case after the first one.
In 1961, the Supreme Court upheld the registration requirement itself in Communist Party v. Subversive Activities Control Board, but explicitly reserved judgment on what would happen when the government tried to impose the consequences of that registration.8Justia U.S. Supreme Court Center. Communist Party v. SACB, 367 U.S. 1 (1961) That was the government’s high-water mark.
In Aptheker v. Secretary of State (1964), the Court struck down the automatic passport ban on members of Communist organizations as an unconstitutionally broad restriction on the right to travel under the Fifth Amendment’s due process clause. The law drew no distinction between active leaders and passive members.
In Albertson v. Subversive Activities Control Board (1965), the Court invalidated the requirement that individual members register, holding that it violated the Fifth Amendment protection against self-incrimination. Because Party membership could itself be evidence in a criminal case, forcing a person to admit it on a government form compelled them to help build the prosecution’s case.9Justia U.S. Supreme Court Center. Albertson v. SACB, 382 U.S. 70 (1965)
In United States v. Robel (1967), the Court struck down the prohibition on Party members working at defense facilities, holding that the provision “literally establishes guilt by association alone” and swept in passive members, people in nonsensitive positions, and members who rejected the Party’s unlawful aims.10Justia U.S. Supreme Court Center. United States v. Robel, 389 U.S. 258 (1967)
Congress repealed the registration provisions in 1968. The Subversive Activities Control Board operated with diminished authority until President Nixon issued an executive order abolishing it, and the Board wound up its affairs in 1973.
What Still Applies Today
The Act was never repealed wholesale, and a few narrow provisions survive.
The most significant is 50 U.S.C. § 783, which makes it a federal crime for a government officer or employee to communicate classified information to someone they know or have reason to believe is an agent of a foreign government. The same section makes it illegal for a foreign agent to knowingly obtain or attempt to obtain classified information from a U.S. government employee. Violations carry a fine of up to $10,000, up to ten years in prison, and permanent disqualification from any federal office or position of trust. The government can also seize property derived from or used to facilitate the offense.11Office of the Law Revision Counsel. 50 USC 783 – Offenses
The other, 50 U.S.C. § 797, makes it a misdemeanor to willfully violate posted security regulations at Department of Defense or NASA properties, punishable by a fine, up to one year in prison, or both. The regulation must be posted in a visible location to be enforceable.12Office of the Law Revision Counsel. 50 USC 797 – Penalty for Violation of Security Regulations and Orders
The registration system, the Subversive Activities Control Board, the passport and defense-employment bans, and the emergency detention authority are all gone. What remains are the criminal provisions on classified information and defense-facility security, which stand on their own and no longer depend on the Cold War machinery the rest of the statute tried to build.