Answer:
The Watergate scandal
Step-by-step explanation:
Although Nixon had several achievements during his term, he is, perhaps, best remembered for being accused of being involved in the Watergate Scandal, an event that increased American's skepticism about government and that rocked his administration.
Such event was the scandal resulting from the arrest of five burglars in the office of the Democratic National Committee in June 1972 that were connected to President Richard Nixon’s reelection campaign. The burglars had been caught wiretapping phones and stealing documents.
Afterward, the President came to be in trouble with justice for trying to cover the crime and the documents, so, in order to avoid impeachment, he soon decided to resign from office.