 He was chosen chairman of a noted mass reform meeting held at Cooper Union on 4 September 1871, and his speech on that occasion was one of the most fearless and outspoken of any in its denunciation of the official thieves.Largely involved in voting the corrupt Tweed administration out of office, Havemeyer was nominated by the Republican Party Convention as a candidate for Mayor of New York on 1 October 1872.Although he at first declined to accept the nomination, the decision was supported by the Committee of 70 and the United Reform Convention, and he once again returned to successfully defeat Tammany Hall candidate Abraham R. Lawrence and James O'Brien to be elected and become Mayor for a third time, the first candidate since DeWitt Clinton to do so.