That's the take in this recent profile at New York magazine. The far left blogosphere first stung Lieberman when his 2004 bid for the Democratic presidential nomination fell flat but then really turned him towards the GOP following his 2006 Senate primary race. In Lieberman's view, powerful bloggers have hijacked his party, especially on foreign policy. From the article:

The 2004 debacle was Lieberman's first introduction to a new force, the netroots, a loose collection of leftist blogs including and DailyKos. The way the senator sees it, those groups have been "taking the party in a direction that's bad for America: take-no-prisoners, partisan attack politics." Their influence, he says, has made the Democrats "litmus-testy" and "reflexively antiwar."

But Lieberman hadn't felt the full wrath of the blogs until his 2006 reelection bid. Online activists, including the coalition Trippi had built for Dean, were united behind Ned Lamont, a young businessman with no national-office experience but a vocal antiwar stance. To Lieberman, the blogs' power in online fund-raising and event organizing--and the vitriol used to fuel it all--came as a shock. (The senator's own Website, by contrast, crashed on the eve of the primary; his campaign blamed it on Lamont hackers until an FBI probe concluded that shoddy programming was the culprit.) On August 8, 2006, Lamont won the primary with 52 percent of the vote. "For the sake of our state, our country, and my party," proclaimed Lieberman, "I cannot and will not let that result stand." The inclusion of "party" in that sentence was jaw-dropping...

...The real reason he's backing McCain, Lieberman says, is because he believes in the kind of foreign policy that the Democrats don't provide anymore: unflinching on Iraq, Iran, and Russia, and unfailingly loyal to Israel (he invokes Nixon's line about "loading every plane" with weapons for Israel to explain what kind of president McCain will be). Lieberman believes foreign policy is the defining issue of the day, and sees Obama's nomination as the regrettable result of a knee-jerk, blog-fueled peacenik mentality among the Democrats. "Last year, at the DailyKos convention, just about all of the candidates came, and the Democratic Leadership Council held a convention and none came," he says. In July, following an online outcry, Lieberman notes, Obama called a second press conference in one day to clarify his position on Iraq troop withdrawal.

Lieberman sees this zigzag as evidence that Obama takes his marching orders from the blogs. "In 2007," he tells me, "netroots and controlled the agenda--they endorsed Obama like they endorsed Ned Lamont, and did to Hillary what they did to me in 2006." Lieberman, who often brings up Lamont without provocation, seems to view the McCain-Obama matchup as his battle with Lamont writ large on the national canvas: a voice-of-reason maverick beholden to no one but his conscience pitted against a cocky line-cutter with no experience. "The lesson Joe learned about the netroots," says a onetime colleague, "is now the frame he will put around any situation, even when it doesn't apply." An even less charitable view of Lieberman's embrace of McCain holds that it's all about payback for the way the Democrats treated him in the '04 election and in Connecticut. "If you're a nail, the whole world looks like a hammer," says the same ex-colleague. "He was hurt, and to an extent, he is still working through it."