The situation that resulted in president andrew johnson's impeachment was, at its heart, an issue surrounding a) reconstruction of the south. b) his nominees to the supreme court. c) expansion into indian territories. d) a secret treaty with great britain.

The correct answer is A. Reconstruction.

Even though one of the most well known formal charges against Andrew Johnson was his violation of the Tenure of Office Act, for firing Edward Stanton without Congressional approval, the underlying reason for his impeachment was his Reconstruction policies. Many northern politicians felt that he did not adequately punish the former Confederate states for their role in starting the Civil War.