The Watergate scandal was a 1972 break-in at the Democratic National Committee headquarters at the Watergate Hotel in Washington, D.C. by members of Richard Nixon's administration and the resulting cover-up which led to the resignation of the President. The burglars' aim was to plant listening devices, while disguised as common criminals to provide cover. They were informally called the "plumbers unit" to "plug leaks," and included former members of the CIA. Though then-President Nixon had endured two years of mounting political embarrassments, the court-ordered release in August 1974 of a "smoking gun tape" about the burglaries brought with it the prospect of certain impeachment for Nixon; he resigned only four days later, on August 9, 1974, making him the only U.S. President to have resigned from office.

On June 17, 1972, Frank Wills, a security guard working at the office building of the Watergate complex office space, residential buildings and a hotel, noticed a piece of tape on the door between the basement stairwell and the parking garage. It was holding the door unlocked, so Wills removed it, assuming the cleaning crew had put it there. Later, at around 2 a.m., he returned and discovered that the tape had been replaced. Suspicious, Wills then contacted the D.C. police.

After the police came, five men  Bernard Barker, Virgilio González, Eugenio Martínez, James W. McCord, Jr. and Frank Sturgis  were discovered and arrested for breaking into the headquarters of the Democratic National Committee. The men supposedly had broken into the same office on May 27 and 28 as well, and had returned intending to fix wiretaps that were not working.

The connection between the Watergate burglary and the President's re-election campaign fundraising committee was highlighted by media coverage of the break-in. In particular, investigative coverage by The Washington Post and The New York Times fueled focus on the event. The coverage dramatically increased the profile of the crime and consequent political stakes. Fed tips by an anonymous source they would later identify only by the code name "Deep Throat(William Mark Felt Sr.)," Post reporters Bob Woodward and Carl Bernstein uncovered information suggesting that knowledge of the break-in and attempts to cover it up led deep into the Justice Department and even the White House itself. Rather than ending with the trial and conviction of the burglars, the investigations grew broader; a Senate committee chaired by Senator Sam Ervin was set up to examine Watergate and started to subpoena White House staff.

On April 30, 1973, Nixon was forced to ask for the resignation of two of his most influential aides, H. R. Haldeman and John Ehrlichman, both of whom would soon be indicted and ultimately go to prison. He also fired White House Counsel John Dean, who had just testified before the Senate and would go on to become the key witness against Nixon himself.

On the same day, Nixon appointed a new Attorney General, Elliot Richardson, and gave him authority to designate, for the growing Watergate inquiry, a special counsel who would be independent of the regular Justice Department hierarchy, to preserve his independence. On May 19, Richardson named Archibald Cox to the position. Televised hearings had begun two days before.

The hearings held by the Senate Committee, in which Dean was the star witness and in which many other former key administration officials gave dramatic testimony, were broadcast from May 17, 1974 to August 7, 1974, causing devastating political damage to Nixon. Each network maintained coverage of the hearings every third day, starting with ABC on May 17 and ending with NBC on August 7. An estimated 85 percent of Americans with television sets tuned in to at least one portion of the hearings.

Perhaps the most memorable question of the hearings came when Republican Senator Howard Baker of Tennessee asked "What did the President know, and when did he know it?", which focused attention for the first time on Nixon's personal role in the scandal.

On July 13, 1974, Donald Sanders, the Assistant Minority Counsel, asked Alexander Butterfield if there were any type of recording systems in the White House. Butterfield answered that, though he was reluctant to say so, there was a system in the White House that automatically recorded everything in the Oval Office. The shocking revelation radically transformed the Watergate investigation. The tapes were soon subpoenaed by first special prosecutor Archibald Cox and then the Senate, as they might prove whether Nixon or Dean was telling the truth about key meetings. Nixon refused, citing the principle of executive privilege, and ordered Cox, via Attorney General Richardson, to drop his subpoena.

On January 28, 1974, Nixon campaign aide Herbert Porter pleaded guilty to the charge of lying to the FBI during the early stages of the Watergate investigation. On February 25, Nixon's personal lawyer Herbert Kalmbach pleaded guilty to two charges of illegal election-campaign activities. Other charges were dropped in return for Kalmbach's cooperation in the forthcoming Watergate trials.

On March 1, 1974, former aides of the President, known as the Watergate Seven  Haldeman, Ehrlichman, Mitchell, Charles Colson, Gordon C. Strachan, Robert Mardian and Kenneth Parkinson — were indicted for conspiring to hinder the Watergate investigation. The grand jury also secretly named Nixon as an unindicted co-conspirator. Dean, Magruder and other figures in the scandal had already pleaded guilty. Charles Colson stated in his book Born Again that he was given a report by a White House aide that clearly implicated the CIA in the whole Watergate scandal and showed an attempt to implicate him as the one responsible.

On April 7, the Watergate grand jury indicted Ed Reinecke, Republican lieutenant governor of California, on three charges of perjury before the Senate committee. On April 5, former Nixon appointments secretary Dwight Chapin was convicted of lying to the grand jury.

Nixon's position was becoming increasingly precarious, and the House of Representatives began formal investigations into the possible impeachment of the President. The committee's opening speeches included one by Texas Representative Barbara Jordan that catapulted her to instant nationwide fame. The House Judiciary Committee voted 27 to 11 on July 27, 1974 to recommend the first article of impeachment against the President: obstruction of justice. The second (abuse of power) and third (contempt of Congress) articles were passed on July 29 and July 30, respectively.

In August, the previously unknown tape from June 23, 1972 was released. Recorded only a few days after the break-in, it documented Nixon and Haldeman formulating a plan to block investigations by having the CIA falsely claim to the FBI that national security was involved. The tape was referred to as a "smoking gun". With this last piece of evidence, Nixon's few remaining supporters deserted him. The ten congressmen who had voted against all three Articles of Impeachment in committee announced that they would all support impeachment when the vote was taken in the full House. Throughout this time, Nixon still denied any involvement in the ordeal.

Nixon's support in the Senate was weak as well. After being told by key Republican Senators that enough votes existed to convict him, Nixon decided to resign. In a nationally televised address on the evening of August 8, 1974, he announced he would resign effective noon on August 9. Though Nixon's resignation obviated the pending impeachment, criminal prosecution was still a possibility. He was immediately succeeded by Gerald Ford, who on September 8, 1974, issued a pardon for Nixon, immunizing him from prosecution for any crimes he may have committed as President. Nixon proclaimed his innocence until his death, although his acceptance of the pardon was construed by many as an admission of guilt. He did state in his official response to the pardon that he "was wrong in not acting more decisively and more forthrightly in dealing with Watergate, particularly when it reached the stage of judicial proceedings and grew from a political scandal into a national tragedy."

Charles Colson pleaded guilty to charges concerning the Ellsberg case; in exchange, the indictment against him for covering up the activities of CRP was dropped, as it was against Strachan. The remaining five members of the Watergate Seven indicted in March went on trial in October 1974, and on January 1, 1975, all but Parkinson were found guilty. In 1976, the U.S. Court of Appeals ordered a new trial for Mardian; subsequently, all charges against him were dropped. Haldeman, Ehrlichman and Mitchell exhausted their appeals in 1977. Ehrlichman entered prison in 1976, followed by the other two in 1977.

The effects of the Watergate scandal did not by any means end with the resignation of President Nixon and the imprisonment of some of his aides. The effect on the upcoming Senate election and House race only three months later, was enormous; voters, disgusted by Nixon's actions, became thoroughly disillusioned with the Republican Party. In that Election, the Democrats gained five seats in the Senate and a remarkable 49 in the House. (See: Watergate babies)

Indirectly, Watergate was the cause of new laws leading to extensive changes in campaign financing. It was a major factor in the passage of amendments to the Freedom of Information Act in 1986, as well as laws requiring new financial disclosures by key government officials.

While not legally required, other types of personal disclosure, such as releasing recent income tax forms, became expected. Presidents since Franklin D. Roosevelt had recorded many of their conversations, but after Watergate this practice purportedly ended.

Watergate led to a new era in which the mass media became far more aggressive in reporting on the activities of politicians. For instance, Wilbur Mills, a powerful congressman, was in a drunken driving accident. The incident, similar to others which the press had previously never mentioned, was reported, and Mills soon had to resign from his position as the chairman of the United States House Committee on Ways and Means. In addition to reporters becoming more aggressive in revealing the personal conduct of key politicians, they also became far more cynical in reporting on political issues. A new generation of journalists, emboldened by the success of Bob Woodward and Carl Bernstein, embraced investigative reporting and sought to uncover new scandals in the increasing amounts of financial information being released about politicians and their campaigns.

Since Nixon and many senior officials involved in Watergate were lawyers, the scandal severely tarnished the public image of the legal profession.^[4] In order to defuse public demand for direct federal regulation of lawyers (as opposed to leaving it in the hands of state bar associations or supreme courts), the American Bar Association (ABA) launched two major reforms. First, the ABA decided that its existing Model Code of Professional Responsibility (promulgated 1969) was a failure, and replaced it with the Model Rules of Professional Conduct in 1983. The MRPC has been adopted in part or in whole by 44 states. Its preamble contains an emphatic reminder to young lawyers that the legal profession can remain self-governing only if lawyers behave properly. Second, the ABA promulgated a requirement that law students at ABA-approved law schools take a course in professional responsibility (which means they must study the MRPC). The requirement remains in effect.

The Watergate scandal left such an impression on the national and international consciousness that many scandals since then have been labeled with the suffix "-gate" — such as Koreagate, Contragate/Iran-gate, Whitewatergate, Travelgate, Fornigate/Monicagate/Zippergate, Filegate, and Memogate/Rathergate in the US, Tunagate in Canada, Dianagate/Squidgygate and Thatchergate in the UK, and even Pemexgate and Godzillagate in Hungary, Toallagate in Mexico, Kazakhgate in Kazakhstan, Narcogate in Argentina, and Iraq-gate in Finland. Moreover, the judging scandal in the pairs event at the 2002 Winter Olympics in which a controversial double-gold medal was awarded to Russians Yelena Berezhnaya & Anton Sikharulidze and Canadians Jamie Salé & David Pelletier was termed "Skategate." A 2003 scandal involving a group of Poland's key political figures and a Polish media magnate Lew Rywin was frequently referred to in Polish media as "Rywingate." Other impressions included Colegate, Sheikgate and Edgate. In 2005, a scandal concerning the legitimacy of Gloria Macapagal Arroyo's reelection as President of the Philippines, due to an alleged conversation Arroyo held with an official from the Commission on Elections, was named "Gloriagate".

According to Thomas J. Johnson, professor of journalism at Southern Illinois University, During Nixon's final days, Secretary of State Henry Kissinger boldly predicted that history would remember him as a great president and that Watergate would be relegated to a minor footnote.