The Alien Registration Act or Smith Act (18 USC 2385) of 1940 made it illegal for anyone in the United States to advocate overthrowing the government. It also required all non-citizen adult residents to register. The act aimed to identify members of the Communist Party of the United States of America.
... it lays stress on the passive
qualities and does not touch with firmness the
string of active service in the world. That which
makes it acceptable to all Christians ...