One man asserts he was "Deep Throat":
He was one of the few who knew of a top-secret fund that paid the men who broke into the Watergate Hotel. Woodward and Bernstein found the bookkeeper for Nixon's re-election committee who told them who was paid and how much they were paid. When the FBI interviewed her, she wrote down what she thought were the exact transactions from the fund. Dean got these reports by promising L. Patrick Gray that they would go straight to the president. They were given to Fielding instead.
Woodward called Fielding for confirmation of the transactions. Fielding confirmed, not knowing that the bookkeeper would later admit to making a mistake with the numbers.
"This was ironic because (Woodward and Bernstein) weren't following a two source rule," Gaines said. "They had one source that went around in a circle … with the wrong information."
Fielding was one of the few people connected to the White House during Watergate who never saw his name in the Washington Post. Katherine Chenow, secretary to Watergate organizers E. Howard Hunt and G. Gordon Liddy, did not keep Fielding as anonymous as he would have liked.
She was on vacation in London when Dean asked Fielding to bring her back to prepare her for FBI questioning. Bernstein decided to call Chenow when he found a subpoena issued by the FBI for her phone records. After Chenow hung up with Bernstein, she realized she had told him too much about Watergate and called Fielding. The conversation they had was found by Gaines' students in the National Archives.
Fielding's name was omitted in the article by Bernstein. He was referred to only as a "White House aide".
In All the President's Men, Fielding is mentioned by name as the one who brought Chenow back from London. However, this was in 1974, after Fielding had begun working at Wiley, Rein and Fielding.
Fielding was also referred to as a White House aide in a Washington Post story detailing the cleaning out of Hunt's safe. John Erlichman, Nixon's assistant, was told to get rid of potential evidence and files detailing the Watergate break-in that Hunt kept in his safe. Erlichman gave the job to Dean who asked Fielding to help him.
Fielding gave Woodward details of conversations between Dean and Ehrlichman and Dean and Gray when they were deciding what to do with the "political dynamite" that was in Hunt's safe. When compared to Dean's testimony, the quotes are almost exact. Deep Throat must have been at the scene.
The only others that could have heard these conversations are either dead or have left government while Deep Throat was still providing information.
Assuming that Deep Throat was only one person, the only plausible suspect is Fielding.
Dean admitted during Watergate testimony that Fielding knew more about the "plumber's unit" than he did. The plumber's unit was a group of White House officials who organized Watergate and were in charge of plugging leaks in the Nixon administration. They were also involved in the burglary of Daniel Ellsberg's office, the psychiatrist who leaked the Pentagon Papers.
Donald Segretti was a lawyer who pleaded guilty to hiring agents to ruin Democratic campaigns. He came to Dean and asked for legal help after the FBI contacted him for questioning. Fielding met with Segretti before the interview and had access to the FBI file afterward.
http://www.dailyillini.com/apr03/apr23/news/stories/news_story01.shtml
Hard to believe he would be appointed to the commission with this history, but apparently he can be trusted to keep a secret.
