Can you keep a secret? Really, really keep a secret . . . like, for 30 years?

A big secret, a secret of more than 30 years, was revealed in Washington this week, and this newspaper had the big role in keeping the secret.

To understand why a secret is such big news, you need to know a little about one of the great scandals involving a president of the United States.

In 1972, President Richard M. Nixon, a Republican, was running for reelection. In June of that year, the offices of the Democrats in Washington were broken into by people trying to figure out how the Democrats were going to try to beat Nixon. The Democrats' offices were in a hotel and office building called the Watergate. That's where the scandal got its name.

The Watergate break-in and efforts by Nixon and his aides to cover it up led to investigations by Congress. Nixon faced impeachment -- being formally charged with crimes by the House of Representatives -- so he resigned in August 1974, becoming the only president to quit the job. Some of his top aides went to prison for their roles in Watergate.

So what does this have to do with a secret and The Washington Post?

In 1972, Post reporters Bob Woodward and Carl Bernstein began writing stories for the newspaper about the break-in and the White House's involvement in it.

Good reporters get information from a lot of people, known as sources. Woodward and Bernstein had many sources for their Watergate stories. One of them, though, was a key source, a man in a position to know lots about the scandal. He let Woodward and Bernstein know if they were on the right track as they pursued the story.

This source didn't want his name in the paper because he could get in trouble. He became known in the Post newsroom (and later around the country and world) as Deep Throat. Only Woodward, Bernstein and their editor, Benjamin C. Bradlee, knew Deep Throat's real name. The three had promised Deep Throat that they wouldn't reveal his name until after he died.

Earlier this week, Vanity Fair magazine reported that W. Mark Felt was Deep Throat. Felt, now 91 and living in California, was the No. 2 official at the Federal Bureau of Investigation during much of Watergate. The magazine article was based on information from Felt's family.

The Post then confirmed that Felt was Deep Throat, bringing to an end this well-kept secret.

-- Tracy Grant

W. Mark Felt's role was kept secret for more than 30 years.Dustin Hoffman, left, and Robert Redford played Post reporters Bernstein and Woodward in "All the President's Men." The movie, now on DVD, made source Deep Throat famous.