Answer: 2. He defied the Congress on the appointment of cabinet members
Andrew Johnson’s defiance of the Congress on their stand on the appointment of cabinet members best describes the underlying reason for his impeachment. Option number 2 is therefore the correct answer.
Andrew Johnson was impeached in the year 1868 due to an accumulation of reasons, but the most prominent of them was because he repeatedly abused his power as the president of the United States of America. On several occasions, Andrew Johnson abused his presidential authority and made decisions that were against the law, and one of such decisions led to the end of his tenure.
While the Congress was out of session, Andrew Johnson attempted to take over from Edwin M. Stanton, the Secretary of War with Ulysses S. Grant, a military leader, who took over as the temporary Secretary of War for 5 months. Andrew Johnson sought to replace Edwin M. Stanton because they often had quarrels between themselves.