Agree. Churchill calls for the violent overthrow of the United States government.
Congress passed the Smith Act in 1940 -- making it unlawful to advocate the violent overthrow of the U.S. government.
The Smith Act of 1940 5 made it a criminal offense for anyone to knowingly or willfully advocate, abet, advise, or teach the duty, necessity, desirability, or propriety of overthrowing the Government of the United States or of any State by force or violence, or for anyone to organize any association which teaches, advises, or encourages such an overthrow, or for anyone to become a member of or to affiliate with any such association.
Ch. 439, 54 Stat. 670, 18 U.S.C. Sec. 2385.