Seditious conspiracy (18 U.S.C. § 2384) is a crime under United States law. It is stated as follows:
If two or more persons in any State or Territory, or in any place subject to the jurisdiction of the United States, conspire to overthrow, put down, or to destroy by force the Government of the United States, or to levy war against them, or to oppose by force the authority thereof, or by force to prevent, hinder, or delay the execution of any law of the United States, or by force to seize, take, or possess any property of the United States contrary to the authority thereof, they shall each be fined or imprisoned not more than 20 years, or both.
For a seditious conspiracy charge to be effected, a crime need only be planned, it need not be actually attempted. According to Andres Torres and Jose E. Velazquez, the accusation of seditious conspiracy is of political nature and was used almost exclusively against Puerto Rican independentistas in the twentieth century. However, the act was also used in the twentieth century against communists and radicals (United Freedom Front, the Provisional IRA in Massachusetts), neo-Nazis, and Islamic terrorists including Omar Abdel-Rahman. This is respective of the state sedition laws, used to persecute hundreds of communists, socialists and labor leaders.
The federal government has never won a sedition case against militia-types or neo-Nazis. Since World War I, they have won numerous seditious conspiracy cases against Puerto Rican independentistas, communists and others on the left, but no one on the radical right has ever been convicted of plotting to overthrow by force of arms the government of the United States.