Thirty years after their aggressive stories on Watergate felled Nixon in August 1974, the two Post reporters, Bob Woodward and Carl Bernstein on Tuesday confirmed that Felt was Deep Throat after Vanity Fair magazine and Felt's family members made his role public.
The unmasking of Deep Throat solves one of the greatest political and journalistic mysteries of modern times and ends three decades of speculation on his identity by historians and political observers.
"W. Mark Felt was Deep Throat and helped us immeasurably in our Watergate coverage," Woodward and Bernstein said in a joint statement posted on the Post's website.
Vanity Fair had reported earlier on Tuesday that Felt, now a 91-year-old retiree living in Santa Rosa, California, had told the magazine and his family that he was the Post's anonymous source.
"I'm the guy they used to call Deep Throat," Felt told lawyer John O'Connor, author of the magazine story.
Nixon resigned in August 1974
after the Watergate expose
Felt's grandson told reporters on Tuesday his grandfather was "an American hero" for his role in uncovering the Watergate scandal, and his daughter said he had "a big grin" upon learning of the Vanity Fair article.
Woodward and Bernstein had refused for decades to reveal the name of their source, spawning multiple books, documentaries and investigations guessing at his identity.
Only three people - Woodward, Bernstein and former Post Editor Ben Bradlee - knew his name, and they vowed not to reveal it until after his death.
The Post quoted Bradlee as saying that knowing Deep Throat was a top FBI official gave him confidence about the newspaper's reporting on Watergate.
"The No. 2 guy at the FBI, that was a pretty good source," Bradlee told the Post.
Felt had always been on the short list of potential Deep Throats. The source was instrumental to the Post's reporting on the Watergate scandal that led to Nixon's resignation in August 1974 - the only resignation of a US president in history.
Nixon resigned after it became clear the US House of Representatives would impeach him for a string of transgressions named after the famous break-in of Democratic national headquarters at the Watergate office complex in Washington.
Vanity Fair said Felt's family learned of his role in Watergate in 2002, but the former FBI No. 2 resisted coming forward. His family eventually convinced him that his actions were heroic and he could perhaps profit from the revelation of his role, the magazine said.
Felt's grandson, Nick Jones, told reporters in Santa Rosa that his grandfather was "an American hero who went well above and beyond the call of duty at much risk to himself to save the country from a horrible injustice".
"My grandfather is pleased that he is being honoured for his role as Deep Throat with his friend Bob Woodward," Jones said.
Woodword secretly met Felt
at isolated settings
Felt's daughter spoke to Woodward, who visited Felt in 1999, by phone more than a half-dozen times to discuss a potential joint announcement, Vanity Fair said.
But Woodward would often begin those conversations with a caveat, the magazine said, saying: "Just because I'm talking to you, I'm not admitting that he is who you think he is."
The magazine said Woodward was concerned that Felt's family was pushing Felt, whose health and mental sharpness were declining with age, toward exposure against his will.
According to the book All the President's Men - Woodward's and Bernstein's account of their Watergate reporting - Deep Throat would often meet Woodward late at night in secluded locations, including underground Washington, DC parking lots, to help him with information that kept the reporters moving ahead on the story.
The list of potential Deep Throats - the nickname came from a porn movie in circulation at the time - has included then-FBI Director Patrick Gray, Nixon chief of staff Alexander Haig, former Secretary of State Henry Kissinger, former Nixon speechwriter Patrick Buchanan and even former President George Bush, father of the current president and head of the Republican National Committee during the scandal.
Felt had denied in the past that he was Deep Throat, but as a top FBI official he would have had access to many of the details of the scandal. He was passed over by Nixon for the top FBI job, giving him a potential motive.