Ashley suspected President Andrew Johnson of complicity in President Lincoln's assassination, and criticized the successor president for attempting to veto extensions of the Freedmen's Bureau, the Civil Rights Bill and the Reconstruction Acts. He suspected Johnson's ties with southern oligarchs. In January 1867, Ashley initiated impeachment proceedings against Johnson, and the following February the House formally charged Johnson with "usurpation of power and violation of law by corruptly using the appointing, pardoning, and veto powers, by disposing corruptly of the property of the United States, and by interfering in elections." However, Johnson was acquitted by the Senate in May 1868.