Though Nixon did not consider the environmental advances he made in office an important part of his legacy, he did establish the United States Environmental Protection Agency and enforced legislation such as the 1973 Endangered Species Act. However, he vetoed the Clean Water Act of 1972, deeming the legislation too expensive.

Nixon ended American involvement in the Vietnam War in 1973, signing the Paris Peace Accords, which implemented a cease fire and allowed for the withdrawal of remaining American troops without requiring the 160,000 North Vietnam Army regulars located in the South to withdraw. Once American combat support ended, there was a brief truce, before fighting broke out again. North Vietnam conquered South Vietnam in 1975.

The Watergate scandal stemmed from the Nixon administration's involvement in the June 17, 1972 burglary of the Democratic National Committee headquarters at the Washington, D.C. Watergate Office Building.

"Deep Throat" was first introduced in the February 1974 book All the President's Men by Washington Post reporters Bob Woodward and Carl Bernstein. Deep Throat was a key source of information behind a series of articles that introduced the misdeeds of the Nixon administration to the general public. The scandal eventually led to the resignation of President Nixon, as well as to prison terms for White House Chief of Staff H. R. Haldeman, G. Gordon Liddy, Egil Krogh, White House Counsel Charles Colson, former United States Attorney General John N. Mitchell, John Dean, and presidential adviser John Ehrlichman.

On the evening of Saturday, October 20, 1973, after Cox subpoenaed the President's Oval Office tapes, Nixon ordered Attorney General Elliot Richardson to fire the Special Prosecutor. Richardson refused and resigned effective immediately. Nixon then ordered Deputy Attorney General William Ruckelshaus to fire Cox. Ruckelshaus refused, and also resigned. Nixon then ordered the third-most-senior official at the Justice Department, Solicitor General Robert Bork, to fire Cox. Bork carried out the dismissal as Nixon asked, and the series of dismissals/firings became known as the Saturday Night Massacre.

Nixon vetoed a total of 43 bills (26 regular vetoes and 17 pocket vetoes), 7 of which were overruled by Congress.

On October 10, 1973, Vice President Spiro Agnew resigned for reasons unrelated to Watergate. He was convicted on charges of bribery, tax evasion and money laundering during his tenure as governor of Maryland.

Senate Minority Leader Hugh Scott, Senator Barry Goldwater, and House Minority Leader John Jacob Rhodes met with Nixon shortly after the release of the "Smoking Gun Tape" which proved the President knew about the burglary and tried to thwart the investigation. Rhodes told Nixon he faced certain impeachment in the House. Scott and Goldwater told the president that he had, at most, only 15 votes in his favor in the Senate, far fewer than the 34 needed to avoid removal from office. Nixon resigned the presidency on August 9, 1974.

The Justice Department pondered a Nixon indictment after his resignation. Internal memos show officials struggling with Article I, Section 3, Clause 7 of the Constitution, which states that a person removed from office by impeachment and conviction "shall nevertheless be liable to Indictment, Trial, Judgment, and Punishment, according to the Law." But there was no mention in the Constitution about a President who had resigned from office. A month later, President Gerald Ford ended this debate by pardoning Nixon.

Nixon suffered a severe stroke on April 18, 1994, while preparing to eat dinner in his Park Ridge, New Jersey home. He was taken to New York Hospital-Cornell Medical Center in Manhattan, initially alert but unable to speak or to move his right arm or leg. Damage to the brain caused swelling and Nixon slipped into a deep coma. He died at 9:08 p.m. on April 22, 1994, with his daughters at his bedside. He was 81 years old.