Answer:
He believed he had not violated the Constitution. Johnson argued that the Tenure of Office Act was unconstitutional because it interfered with the president's constitutional authority to remove and appoint members of the Cabinet.
Explanation:
The primary reason why Johnson was found innocent of violating the Tenure of Office Act when he removed Secretary of War Edwin Stanton was that he believed he had not violated the Constitution. Johnson argued that the Tenure of Office Act was unconstitutional because it interfered with the president's constitutional authority to remove and appoint members of the Cabinet. The legal and constitutional arguments played a significant role in his defense during the impeachment trial.