The long-awaited naming of Deep Throat has become a reminder of how vital anonymous sources can be in breaking an important story - and how tough it is to do it in a way that preserves public confidence.
These are lessons that go back before Watergate, and they continue to be learned by today's crop of reporters. But rarely do they generate the buzz that Deep Throat has in the past week.
Former FBI Deputy Director Mark Felt turns out to be a more complex character than the earnest civil servant portrayed by Hal Holbrook in the film "All the President's Men" - or sketched in the book of the same title by Washington Post reporters Bob Woodward and Carl Bernstein.
Whatever his motives, Mr. Felt was a key player in a fierce bureaucratic turf war between the FBI and the Nixon White House. Moreover, at the same time he was guiding Mr. Woodward through illegalities of the Watergate affair, Felt signed off on nine illegal FBI break-ins for which he would be later convicted and pardoned.
"This city floats on a sea of leaks. It is the currency of this one-company town," says Jonathan Turley, a professor of public interest law at George Washington University Law School. "Some of the most important leaks were done with less than inspiring motives.... Nevertheless, the leak was true and historic."
In this case, indeed, the information provided by Deep Throat made superstars of the two journalists who kept his name secret. Yet anonymous sourcing has as often been a peril in US journalism.
Since Watergate, public confidence in the press has been battered by a succession of reporters who have fabricated stories, often using unnamed hoax sources.
But in the nation's capital, many important stories may never be told without leakers, who often demand anonymity.
For most the 19th century, leaks were the bread and butter of Washington journalism, when much of what the Senate did was behind closed doors. Nominations and treaties were all handled in executive session, and anonymously leaked to press corps favorites.
In 1800, three Republican senators relayed the contents of a Federalist bill that, by a rule change on disputed votes, could have prevented the election of Thomas Jefferson. It prompted the first of many forcible detentions of a journalist by Congress, as well as its first citation for contempt of Congress.
"Leaking has gone on from the earliest days of the Republic," says Senate historian Donald Ritchie. "The leaking of secrets was a mutual act in which both the politician and the reporter participated.... As a price for leaking information, senators expected favorable treatment," he writes in "Press Gallery: Congress and the Washington Correspondents (1991).
Another peril has been the anonymous source who later recants. In 1846, the Washington Daily Times printed allegations that Democrats were plotting a deal over Oregon with Britain. The Senate investigated and editors gave up the names of their anonymous sources - every one of whom denied involvement. Owner and editor were banned from the press gallery and the Times folded.
"What ought to matter to a reporter or a reader isn't motive, but whether the information is accurate or true or not," says Brooks Jackson, a visiting scholar at the Annenberg Public policy Center who covered Watergate for the Associated Press. "For a reporter using an anonymous source, the problem is that you are implicitly vouching for the accuracy of what that source is saying."
Last month, Newsweek retracted its report of abuse of the Koran at Guantánamo Bay, unable to confirm a report by one anonymous source.
Even if the testimony of anonymous sources holds up, their use can undermine public trust. Only 28 percent of the public say they had confidence in newspapers, according to a May 23-26 Gallup poll, the lowest rating since 1973.
One reason is the protection that journalists may give to sources in exchange for information. That protection can compromise coverage.
Deep Throat, for example, "seemed to know everything that the FBI had uncovered, but revealed nothing that cast the bureau in a poor light," writes Senate historian Ritchie in his latest book on the Washington press corps, "Reporting from Washington." (Ritchie correctly predicted that Deep Throat had a connection to the FBI.) It was the Los Angeles Times, not The Washington Post, that first reported the involvement of former FBI agent Alfred Baldwin in monitoring wiretaps for the Watergate burglars.
Anonymous sourcing is so deeply ingrained in the fabric of Washington journalism that Cabinet officials and top White House aides routinely give briefings on background - a practice that news organizations occasionally protest but have done little to budge. Still, anonymously sourced quotes are down one-third since the Reagan years, according to a recent study by the Center for Media and Public Affairs. The national press uses the highest proportion of unnamed sources and the network nightly news uses the lowest.