After 36 years as a full-time reporter at the Chicago Tribune, I retired in 1999 to teach journalism at the University of Illinois at Urbana-Champaign. During that first semester, as the students searched for an investigative project to tackle, I showed them All the President’s Men. This 1976 movie is based on the book by Washington Post reporters Bob Woodward and Carl Bernstein, who won a Pulitzer Prize for the Post in 1973 for their stories about the political scandal known as Watergate. The film, starring Robert Redford as Woodward and Dustin Hoffman as Bernstein, accurately portrays how investigative reporters comport themselves, ask questions, conduct interviews, even the unobtrusive way they hold a notebook. What most intrigued the students, however, were the secret meetings between the Woodward character and a high-level government official, played by Hal Holbrook, that the book referred to only as Deep Throat. The name echoes a 1972 pornographic movie and plays off the term “deep background,” or information provided to a reporter on the condition that the source be neither identified nor quoted directly.

Deep Throat met with Woodward seven times between September 1972 and May 1973 to help the two reporters break several stories about the involvement of Nixon administration officials in the June 17, 1972, burglary of the Democratic National Committee headquarters at the Watergate office-apartment-hotel complex in Northwest Washington. (The burglars, who were seeking information that could be used against Democrats in the upcoming elections, were indicted later for conspiracy, burglary, wiretapping and planting secret listening devices.)

The Post’s stories, along with those of other newspapers and several rulings by Judge John Sirica, the chief judge for the U.S. District Court for the District of Columbia and the Watergate trials, led to televised hearings in the U.S. Senate about the break-in. From these, a riveted nation learned about an administration coverup of the break-in and a covert White House operation that engaged in burglary and political spying. The hearings were followed by impeachment proceedings by the Judiciary Committee of the House of Representatives. But before the full House could vote on whether the president should be impeached, Nixon resigned on August 9, 1974, and Vice President Gerald Ford was sworn in as president. At least 19 high-level officials and other conspirators would plead guilty to or be convicted of various crimes related to Watergate.

Besides adding the suffix "-gate" to our lexicon as an indicator of scandal, and evoking campaign finance reform bills, Watergate resulted in a lasting public distrust of government. It also left one of the century’s most intriguing political mysteries unsolved.

For the past 30 years, guessing the identity of Deep Throat has become something of a parlor game among journalists, pundits and conspiracy theorists. At least three books and scores of articles have delved into the identity of Deep Throat. The list of likely suspects has included former White House aide and current network anchor Diane Sawyer; Nixon’s chief of staff, Alexander Haig; acting FBI director Patrick Gray; and John Sears, one of Nixon’s deputy counsels. At the same time, some have argued that Deep Throat wasn’t one person but a composite of several sources, while others have posited that he was merely a literary invention.

Woodward and Bernstein have both said they will not reveal their secret source’s name until the individual dies, although Woodward did disclose that Deep Throat was a living male. Likewise, Ben Bradlee, executive editor of the Washington Post during the Watergate era, has said he knows Deep Throat’s identity but won’t divulge it. About 75 archival boxes, containing more than 250 notebooks, assorted files, galleys for the book All the President’s Men, and photographs, which the University of Texas bought for $5 million this past April, will be available to the public in the fall of 2004. But documents referring to Deep Throat and other confidential sources will be kept sealed in an undisclosed location until the sources’ deaths.

Why, my students asked, was Deep Throat’s identity still not known after so many years? It was not an easy question to answer. Walt Harrington, a fellow journalism professor at the University of Illinois, once told me he had heard Bradlee say that anyone wanting to learn Deep Throat’s identity should search a computer database for Watergate figures who were actually in Washington at the time of those meetings. To my knowledge, no one had ever done so. Though few organizations would have the resources or motivation to unmask Deep Throat, it seemed a challenging pursuit for my students.

The students read autobiographies of potential suspects and filled a computer spreadsheet with dates, meetings, events and other information. During eight semesters, about 60 undergraduate and graduate students pored over more than 16,000 pages of FBI reports on microfilm in our university library, as well as all the newspaper stories Woodward and Bernstein had written in the first two years of the scandal. From those documents, they concluded that only a member of the FBI or the White House would have had access to the information Deep Throat evidently leaked to Woodward. Later, we concluded that Deep Throat could not be in the FBI after we found a quote in a 1973 Woodward and Bernstein Post story attributed to a "White House" source that was similar in wording to one attributed to Deep Throat in All the President’s Men. In an unpublished early draft of that book, we also read that neither reporter had FBI sources. The admission was later excised, in our view, to protect Deep Throat’s identity.

We obtained the 1972 and ’73 White House staff directories, which listed 72 people in high-level jobs; of those, 39 were living males. The students then ruled out anyone not working at the White House between September 1972 and May 1973, the period when Deep Throat met with Woodward. Newspaper reports showed that some promising Deep Throat candidates, including Chief of Staff Alexander Haig, were out of the country during the time of those meetings. Because the reporters had written that Deep Throat drank Scotch whisky and smoked, the students also eliminated confirmed teetotalers and nonsmokers.

That left just seven candidates: Patrick Buchanan, speechwriter and special assistant to Nixon and later a newspaper columnist and presidential candidate; Stephen Bull, a personal aide to Nixon; David Gergen and Raymond Price, both speechwriters; Jonathan Rose, attorney for regulatory affairs; Gerald Warren, deputy press secretary; and Fred Fielding, an attorney and assistant to White House chief legal counsel John Dean.

In June 2002, "Dateline NBC" interviewed the students about our project. The students said the leading candidate was Buchanan. But a month later, one of them, Jessica Heckinger, got a note from him: "Please thank the class for me—for the unanimous vote. It is one of the few primaries I have won, outside of the Reform Party where I won them all. However, you made some mistakes. Buchanan gave up smoking on the China trip (February ’72) and Buchanan has no motive." It was not a flat-out denial, but most of the students and I found Buchanan’s remarks persuasive. We struck him from the list.

A few weeks later, we got a break. We were trying to determine who on our shortlist would have had knowledge of the secret slush fund controlled by members of Nixon’s reelection campaign committee. This money bank-rolled the Watergate burglars.

Judith Hoback, a bookkeeper for Nixon’s reelection campaign committee, was the general accountant for the fund. In All the President’s Men, Hoback says that soon after the break-in, she deduced that the money she was disbursing might have something to do with the burglary, so she approached the FBI. She told them that cash disbursements of more than $50,000 apiece were given to committee officials Herbert Porter and Jeb Magruder. In their book, Woodward and Bernstein recalled that Hoback had revealed her suspicions about a slush fund to Woodward in an interview. Before the pair published a story about the secret fund in the Post, they confirmed the information, including the amounts, with Deep Throat.

The breadth of Deep Throat’s information surprised my students. How could he have knowledge of the reelection committee’s secret finances?

The students learned that the FBI had shared some of its findings with the White House counsel, John Dean. We did not consider Dean himself to be a candidate because he had left the White House in April 1973. This led us to Dean’s assistant, Fred Fielding, who was already on our shortlist.

In the fall of 2002, student Thomas Rybarczyk dug up a June 1973 letter from Fielding that noted that Dean had given him a summary of a July 1972 FBI report detailing Hoback’s account of the cash transactions. However, Hoback’s recollections of the disbursements were mistaken; she had initially provided the FBI as well as Woodward and Bernstein with incorrect figures. In fact, Magruder had received $20,000, not the $50,000 she remembered. Curiously, though, Deep Throat had confirmed the incorrect figures, which suggests that he gleaned the information from the FBI report given to Dean.

Other clues started pointing us toward Fielding. For instance, Woodward and Bernstein omitted Fielding’s name from stories about the White House counsel’s office. Leaving a key source’s name out of a story is a journalistic commonplace; it not only protects sources but prevents rival reporters from learning the identity of a valuable informant.

As far as we could determine, Fielding shared Deep Throat’s taste for cigarettes and whisky. He had access to information that Deep Throat corroborated for Woodward and Bernstein. And as student Robert Breslin found in 2002, Fielding even fit a characterization of the mysterious source that Woodward and Bernstein deleted from that early, unpublished draft of their book. The reporters wrote that Deep Throat was "perhaps the only person in government in a position to possibly understand the whole scheme and not be a potential conspirator himself."

Fielding, who helped Dean run the White House’s law office during the growing Watergate crisis, left the White House before Nixon resigned and returned to private law practice. In 1981, he became chief counsel to President Reagan and served in the White House for another five years before again returning to private practice. Fielding became a member of the Bush-Cheney transition team in 2000. In 2002, he became a member of the National Commission on Terrorist Attacks Upon the United States. Today, at age 64, he is a senior partner in the law firm Wiley Rein & Fielding LLP in Washington, D.C.

In 1978, Bob Haldeman, Nixon’s first chief of staff, wrote in his book The Ends of Power about his belief that Fielding was Deep Throat and that "only Dean, or his associate, had access from the White House to the CRP [Committee to Re-elect the President], the FBI and the Justice Department during Watergate." Fielding denied the charge at the time. But Woodward has said, as recently as October of this year at a lecture, that "Deep Throat is a source who lied to his family, to his friends and colleagues denying that he had helped us." (Fielding did not respond to Smithsonian magazine’s request for comment.)

When my students contacted Woodward during the first semester of the investigation and asked him if he would talk to us about our investigations of Deep Throat, he declined. When we approached Carl Bernstein to ask him about our final seven suspects, he denounced our project, saying it undermined journalistic principles to reveal the identity of a confidential source.

On April 22 of this year, at a press conference in the Watergate Hotel, I announced that my students and I had deduced that Fred Fielding was indeed Deep Throat. The next day, I got an e-mail from John Dean: "I’ll bet you a hundred dollars that you’re wrong about Fielding."

I took the bet.