In the face of almost certain impeachment, Richard Nixon did the unprecedented, submitting his resignation letter to Secretary of State Henry Kissinger. The move marked the first time a U.S. President had voluntarily relinquished the office. Facing mounting pressure from lawmakers and the public, Nixon's decision came just two days after his attorney general, Archibald Cox, refused to comply with the President's orders to fire the special prosecutor investigating the Watergate affair. With his approval ratings in free fall, Nixon's grip on the presidency began to slip, ultimately forcing him to relinquish the reins to Vice President Gerald Ford.