If you've seen the movie "All the President's Men," you already know this story. The Washington Post assigned two young, relatively unheralded reporters, Carl Bernstein and Bob Woodward, to dig further into a June 1972 burglary at the Democratic National Committee headquarters in Washington D.C.'s Watergate complex.
The two soon discovered connections between the burglary, the Nixon White House and the president's re-election campaign. Helped by an anonymous source they called "Deep Throat," who decades later was revealed to be FBI deputy director W. Mark Felt, Sr., they published stories showing, among other revelations, that the break-in had been financed through campaign contributions, and that Watergate was part of a sprawling conspiracy of political espionage and "dirty tricks" to ensure Nixon got a second term.
Nixon still won re-election, but the Post's revelations helped lead to a Congressional investigation which, in turn, exposed the existence of secret recordings of White House meetings. Those tapes implicated Nixon in efforts to cover up the conspiracy, and in August 1974, he became the first U.S. president to resign [source: Britannica.com].
As Woodward and Bernstein wrote in 2012, "Watergate was a brazen and daring assault, led by Nixon himself, against the heart of American democracy." Without their reporting, he might have succeeded.