In March 1867, Congress adopted the Tenure of Office Act, barring the president from removing certain officeholders, including cabinet members, without the consent of the Senate. Johnson considered this an unconstitutional restriction on his authority. In February 1868, he removed Secretary of War Edwin M. Stanton, an ally of the Radicals. The House of Representatives responded by approving articles of impeachment—that is, it presented charges against Johnson to the Senate, which had to decide whether to remove him from office.
That spring, for the first time in American history, a president was placed on trial before the Senate for “high crimes and misdemeanors.” By this point, virtually all Republicans considered Johnson a failure as president. But some moderates disliked Benjamin F. Wade, a Radical who, as temporary president of the Senate, would become president if Johnson were removed. Others feared that conviction would damage the constitutional separation of powers between Congress and the executive. Johnson’s lawyers assured moderate Republicans that, if acquitted, he would stop interfering with Reconstruction policy. The final tally was 35-19 to convict Johnson, one vote short of the two-thirds necessary to remove him. Seven Republicans had joined the Democrats in voting to acquit the president.
A few days after the vote, Republicans nominated Ulysses S. Grant, the Union’s most prominent military hero, as their candidate for president. Grant’s Democratic opponent was Horatio Seymour, the former governor of New York. Reconstruction became the central issue of the bitterly fought 1868 campaign. Republicans identified their opponents with secession and treason, a tactic known as “waving the bloody shirt.” Democrats denounced Reconstruction as unconstitutional and condemned black suffrage as a violation of America’s political traditions.
They appealed openly to racism. Seymour’s running mate, Francis P. Blair Jr., charged Republicans with placing the South under the rule of “a semi-barbarous race” who longed to “subject the white women to their unbridled lust.”