The cause of the final confrontation between president johnson and congress, which led to the impeachment of the president, was

The Tenure of Office Act. Johnson felt the Act was unconstitutional and removed the Secretary of War, in contravention of the Act, which forbade the President from removing Cabinet members without consent of the Senate. This led to an impeachment, but acquittal by one vote.

Upheld the 1st amendment according to the u.s constitution. freedom of speech being limited in this case yes national emergencies