By Mike Lillis - 04/22/12 01:52 PM EDT
Lieberman, who became an Independent after losing the Democratic primary race in 2006, still caucuses with the Democrats, but said he won't put his weight behind either President Obama or Mitt Romney, the presumptive GOP nominee.
Lieberman, who is retiring at the end of this year, made few friends among Democrats when he came out strongly for Sen. John McCain (R-Ariz.) rather than Obama in the 2008 contest. He suggested the lingering bitterness of that endorsement has influenced his decision to remain silent this year.
"I'm going to try something different this year. I'm going to try to stay out of this one," Lieberman said with a laugh. "You know, I'm not running for reelection. I'm enjoying not being involved in the nastiness of campaigning."
He's not the only senator keeping his cards to his chest. Sen. Joe Manchin (D-W.Va.), a freshman up for reelection, said this week that he's "worried about me," and declined to endorse a presidential candidate.
“I’ll look at the options,” Manchin told the National Journal. “I am just waiting for it to play out. I am not jumping in one way or another."
Lieberman, for his part, said a lingering anxiety among voters amid a volatile economy will lead to a "close and unpredictable" contest.
"The American people are very unsettled. They're very uneasy about the economy, about the government," he said. "This is going to be a very close and unpredictable presidential election, right down to election day."