Investigating the roots of the Obama birthplace conspiracy theory, John Avlon — author of Wingnuts: How the Lunatic Fringe Is Hijacking America, available now from Beast Books — uncovers the first Birther and finds she's a Hillary Clinton supporter also implicated in Dan Rather's exit from CBS.

Plus, read more on Avlon’s new book.

The Birthers were back in force at the National Tea Party Convention in Nashville.

WorldNet Daily founder Joseph Farah used his prime-time speaking slot, broadcast on C-Span, to pump up claims that President Obama was not born in the United States—and received enthusiastic applause from the audience. Birther queen Orly Taitz was in the house, making the rounds as a celebrity conspiracy theorist.

The persistence of this much-debunked rumor is a reminder of how the fringe is blurring with the base in American politics. It provoked conservative Internet impresario Andrew Breitbart into a confrontation with Farah, the new guard vs. the old, with Breitbart arguing that attempts to prove Obama was born abroad are stupid and self-destructive, "a losing issue."

"I determined that I was going to start digging up every bit of dirt that I could find on him and…convince the Democratic Party to dump him and make Hillary the nominee."

The high-profile resurgence of the Birther claims on cable television provoked much self-satisfaction from liberals as the latest evidence of the influence of wingnuts on conservative politics.

But there's an inconvenient truth liberals are going to have to confront: The Birthers began not on the right, but on the left.

Investigations for my new book, Wingnuts, revealed that the Birther conspiracy theory was first concocted by renegade members of the original Obama haters, Party Unity My Ass, known more commonly by their acronym, the PUMAs. They were a splinter group of hard-core Hillary Clinton supporters who did not want to give up the ghost after the bitter 50-state Bataan Death March to the 2008 Democratic nomination.

In the early summer of '08, message boards on sites like PUMAParty.com began lighting up with the ultimate reversal-of-fortune fantasy—that their party's nomination could be overturned on constitutional grounds. "Obama May Be Illegal to Be Elected President!" read one representative e-mail: "This came from a USNA [U.S. Naval Academy] alumnus. It'll be interesting to see how the media handle this...WRITE TO YOUR LOCAL newspaper editors etc. Keep this out there everyday possible. Also write to the DNC too!"

That June, the Obama campaign released his certificate of live birth on its Web site as part of its "fight the smears" effort. Factcheck.org and other organizations examined the document in person and declared it genuine: "Our conclusion: Obama was born in the U.S.A. just as he has always said." But posters at the PUMA sites were unimpressed: "Nobody believes it's for real, except the Kool-Aid drinkers themselves."

A Clinton supporter from Texas known as Linda Starr was particularly fired up by what she later told me was "the daily misogynistic hate speech against Hillary" during the primaries. As a Democratic precinct captain in Medina County, Starr had volunteered for the Clinton campaign during the hotly contested June Lone Star State primary and served as a Clinton delegate at the state convention. But Starr's real talent was as an amateur opposition researcher—she'd dug up dirt against Republican congressional leaders like Dan Burton and Bob Livingston during the Clinton impeachment hearings in the late 1990s. She was also cited as a key source for CBS' discredited election year investigation into George W. Bush's National Guard records that led to Dan Rather's replacement after 24 years as the evening news anchor.

After Clinton's concession, Starr turned her attention to Obama. "I determined that I was going to start digging up every bit of dirt that I could find on him," she told me after I hunted her down in late 2009, "and that hopefully that I would find something against him that would convince the Democratic Party to dump him and make Hillary the nominee."

In the first week of August 2008, as the Democrats were getting ready for their convention in Denver, Starr called Philadelphia attorney Philip Berg and offered a challenge. Berg recalled the conversation for me: "She called me up and said, 'Have you heard about Obama not being national born?' I said, 'Yes.' She said, 'Well, now it's for real, and you're the only attorney in the country with brass balls enough to sue Obama.'"

Berg also had been a Clinton supporter, but he was best-known as a former deputy attorney general of Pennsylvania and a serial unsuccessful Democratic campaigner for statewide office. He also had a reputation as an enthusiastic litigant: In 2004, he filed a 9/11 Truther lawsuit against Bush, alleging that the government allowed the terrorist attacks to happen and that the World Trade Center was destroyed from within. Now he had a new conspiracy to push.

• Peter Beinart: The Tea Partiers’ Phony PopulismOn August 21, 2008, Berg filed the first Birther lawsuit, requesting an injunction to stop the Democratic Convention from going forward and alleging that Obama was born in Kenya, not Hawaii. He faxed notices to the DNC and Obama campaign headquarters, and the next day, he launched the Web site Obamacrimes.com with Starr's assistance. The lawsuit went nowhere. Berg still fumes when recounting his frustration: "[DNC chair] Howard Dean at that point should have called Obama and said 'What's the story, are you natural born or not?'…Obviously there was collusion there and I think when it's all said and done they should all be tried and put in jail." Journalists ignored his efforts, as well. "I wish I could sue them," said Berg, of the media. "If the American public knew what was going on here Obama would be out of office or we never would have had him in office."

Of course, the rush to delegitimize Obama once he was elected president fell to wingnut conservatives, who continue to confuse losing an election with living under tyranny. But this new evidence of the conspiracy theory's roots on the far left is a reminder that wingnuts exist in both parties, wherever anger and absolutism drive people to believe that their political opponents are their personal enemies. Unhinged activists can have a disproportionate influence on our debates.

The far right and the far left can be equally insane, and the extremes end up echoing each other.

John Avlon's new book Wingnuts: How the Lunatic Fringe is Hijacking America is available now by Beast Books both on the web and in paperback. Advance orders can be placed here. He is also the author of Independent Nation: How Centrists Can Change American Politics. Previously, he served as chief speechwriter for New York City Mayor Rudy Giuliani and was a columnist and associate editor for The New York Sun.