Why was president johnson nearly impeached?

Stanton refused to yield, barricading himself in his office, and the House of Representatives, which had already discussed impeachment after Johnson’s first dismissal of Stanton, initiated formal impeachment proceedings against the president. On February 24, Johnson was impeached, and on March 13 his impeachment trial began in the Senate under the direction of U.S. Supreme Court Chief Justice Salmon P. Chase. read more

They claimed that President Johnson had abused the powers of the Presidency, to which impeachment was the only corrective; the failure of impeachment in Johnson's case proved to the petitioners that the Presidency had grown too powerful and the only remaining solution was the abolition of the office. read more