Nixon was accused of covering up the Watergate scandal and lying about it to the American people.
The infamous botched burglary at the Democratic National Committee in Washington was part of a covert, illegal campaign against what Nixon perceived to be his personal and political enemies. Despite enjoying high approval ratings and being on the verge of a crushing landslide election victory, Nixon was a deeply insecure man, believing that his presidency was being constantly undermined by his opponents in politics and the media.
In response, he authorized a covert campaign of burglaries and illegal surveillance designed to dish the dirt on his enemies. When the Watergate burglars were arrested and sent for trial, the White House officially denied all knowledge of the operation. But this turned out to be a total lie. A special Senate investigation committee was set up, and before that committee one of Nixon's aides, John Dean, testified that Nixon had not only known about the Watergate break-in but had actively tried to cover-up evidence of the White House's involvement.
Despite his best efforts to have them suppressed, the secret tapes that Nixon made of his conversations in the Oval Office were released to a shocked, incredulous public. As well as revealing a somewhat potty-mouthed president with a taste for profanity, they showed that Nixon had indeed been involved in the cover-up all along. In the summer of 1974, the House Judiciary Committee approved articles of impeachment against the president for obstructing justice. But before he could be impeached, Nixon resigned, the first president in American history to do so.