Amnesty Act

The Amnesty Act of 1872 was a United States federal law passed on May 22, 1872, which reversed most of the penalties imposed on former Confederates by the Fourteenth Amendment, adopted on July 9, 1868. Section 3 of the Fourteenth Amendment prohibited the election or appointment to any federal or state office of any person who had held any of certain offices and then engaged in insurrection, rebellion, or treason. However, the section provided that a two-thirds vote by each House of the Congress could override this limitation. The 1872 act was passed by the 42nd United States Congress and the original restrictive Act was passed by the United States Congress in May 1866.
Specifically, the 1872 Act removed office-holding disqualifications against most of the secessionists who rebelled in the American Civil War, except for "Senators and Representatives of the thirty-sixth and thirty-seventh Congresses, officers in the judicial, military, and naval service of the United States, heads of departments, and foreign ministers of the United States."
In the spirit of the act, then United States President Ulysses S. Grant, by proclamation dated June 1, 1872, directed all district attorneys having charge of proceedings and prosecutions against those who had been disqualified by the Fourteenth Amendment to dismiss and discontinue them, except as to persons who fall within the exceptions named in the act. President Grant also pardoned all but 500 former top Confederate leaders.
The 1872 Act affected over 150,000 former Confederate troops who had taken part in the American Civil War.