Scrubbing the server looks very bad.

Release of the tapes

The tapes revealed several crucial conversations[41] that took place between the President and his counsel, John Dean, on March 21, 1973. In this conversation, Dean summarized many aspects of the Watergate case, and focused on the subsequent coverup, describing it as a "cancer on the presidency". The burglary team was being paid hush money for their silence and Dean stated: "That's the most troublesome post-thing, because Bob [Haldeman] is involved in that; John [Ehrlichman] is involved in that; I am involved in that; Mitchell is involved in that. And that's an obstruction of justice."[42] Dean continued and stated that Howard Hunt is blackmailing the White House, demanding money immediately; President Nixon replied that the blackmail money should be paid: "…just looking at the immediate problem, don't you have to have – handle Hunt's financial situation damn soon? […] you've got to keep the cap on the bottle that much, in order to have any options."[42]

At the time of the initial congressional impeachment, it was not known if Nixon had known and approved of the payments to the Watergate defendants earlier than this conversation. Nixon's conversation with Haldeman on August 1, 1972, is one of several that establishes this. Nixon states: "Well…they have to be paid. That's all there is to that. They have to be paid."[43] During the congressional debate on impeachment, some believed that impeachment required a criminally indictable offense. President Nixon's agreement to make the blackmail payments was regarded as an affirmative act to obstruct justice.[44]

On December 7, 1973, it was found that an 18½ minute portion of one recorded tape had been erased. Nixon's longtime personal secretary, Rose Mary Woods, said she had accidentally erased the tape by pushing the wrong pedal on her tape player when answering the phone. The press ran photos showing that it was unlikely for Woods to answer the phone and keep her foot on the pedal. Later forensic analysis determined that the tape had been erased in several segments – at least five, and perhaps as many as nine.[45]

Final investigations and resignation

Nixon's position was becoming increasingly precarious. On February 6, 1974, the House of Representatives approved H.Res. 803 giving the Judiciary Committee authority to investigate impeachment of the President.[46][47] On July 27, 1974, the House Judiciary Committee voted 27–11 to recommend the first article of impeachment against the president: obstruction of justice. The House then recommended the second article, abuse of power, on July 29, 1974. The next day, on July 30, 1974, the House recommended the third article: contempt of Congress. On August 20, 1974, the Committee then formally submitted H. Rept. 93-1305 which included the text of the resolution impeaching President Nixon and setting forth articles of impeachment against him.[48][49]

"Smoking Gun" tape

On August 5, 1974, the White House released a previously unknown audio tape from June 23, 1972. Recorded only a few days after the break-in, it documented the initial stages of the coverup: it revealed Nixon and Haldeman meeting in the Oval Office and formulating a plan to block investigations by having the CIA falsely claim to the FBI that national security was involved. Haldeman introduced the topic as follows:

…the Democratic break-in thing, we're back to the–in the, the problem area because the FBI is not under control, because Gray doesn't exactly know how to control them, and they have… their investigation is now leading into some productive areas […] and it goes in some directions we don't want it to go.

After explaining how the money from CRP was traced to the burglars, Haldeman explained to Nixon the coverup plan: "the way to handle this now is for us to have Walters [CIA] call Pat Gray [FBI] and just say, 'Stay the hell out of this …this is ah, business here we don't want you to go any further on it.'" President Nixon approved the plan, and after he was given more information about the involvement of his campaign in the break-in, he told Haldeman: "All right, fine, I understand it all. We won't second-guess Mitchell and the rest." Returning to the use of the CIA to obstruct the FBI, he instructed Haldeman: "You call them in. Good. Good deal. Play it tough. That's the way they play it and that's the way we are going to play it."[50][51]

Nixon denied that this constituted an obstruction of justice, as his instructions ultimately resulted in the CIA truthfully reporting to the FBI that there were no national security issues. Nixon urged the FBI to press forward with the investigation when they expressed concern about interference.[52]

Before the release of this tape, President Nixon had denied any involvement in the scandal. He claimed that there were no political motivations in his instructions to the CIA, and claimed he had no knowledge before March 21, 1973, of involvement by senior campaign officials such as John Mitchell. The contents of this tape persuaded Nixon's own lawyers, Fred Buzhardt and James St. Clair, that "The tape proved that the President had lied to the nation, to his closest aides, and to his own lawyers – for more than two years".[53] The tape, which was referred to as a "smoking gun" by Barber Conable, proved that Nixon had been involved in the coverup from the beginning.

In the week before Nixon's resignation, Ehrlichman and Haldeman unsuccessfully tried to get Nixon to grant them the pardons which Nixon had promised them before their April 1973 resignations.[54]
Resignation
Oliver F. Atkins' photo of Nixon leaving the White House shortly before his resignation became effective, August 9, 1974[55]

The release of the "smoking gun" tape destroyed Nixon politically. The ten congressmen who voted against all three articles of impeachment in the House Judiciary Committee announced they would all support impeachment when the vote was taken in the full House.

On the night of August 7, 1974, Senators Barry Goldwater and Hugh Scott and Congressman John Jacob Rhodes met with Nixon in the Oval Office and told him that his support in Congress had all but disappeared. Rhodes told Nixon that he would face certain impeachment when the articles came up for vote in the full House. Goldwater and Scott told the president that there were not only enough votes in the Senate to convict him, but that no more than 15 Senators were willing to vote for acquittal. Realizing that he had no chance of staying in office, Nixon decided to resign.

"Have I ever said she broke the law? Have I said it disqualifies her? No."

-Morningfog

That means whatever was in those emails was so bad that it would be worth dealing with the controversy of destroying them.