Sen. Joe Lieberman said his conscience demanded that he run as an independent in Connecticut’s Senate race even as his longtime political supporters threw their support to Ned Lamont, the anti-war challenger who defeated the 18-year incumbent in the Democratic primary.

"While I consider myself a devoted Democrat, I am even more devoted to my state and my country," Lieberman said in an interview with The Associated Press on Wednesday, a day after his stunning loss. "I think it would be irresponsible and inconsistent with my principles if I were to just walk off the field."

Even so, top Senate Democrats, including John Kerry and Edward Kennedy of Massachusetts, Harry Reid of Nevada, Frank Lautenberg of New Jersey and Chuck Schumer of New York, said they supported Lamont as the duly elected choice of Connecticut’s Democratic voters.

Sen. Hillary Rodham Clinton stopped short of calling on Lieberman to quit the race but urged the senator to "search his conscience and decide what is best for Connecticut and for the Democratic Party."

Lieberman said he was not bothered by losing the support of his colleagues, noting he lost the primary even with their backing. "In the end, the people make up their own minds, and this is going to be a people’s campaign," he said.

The defeat put Lieberman in the familiar role of a go-it-alone politician. He was the first prominent Democrat to openly criticize President Clinton’s conduct with Monica Lewinsky. His support for the Iraq war and his defense of President Bush also have made him unpopular with members of his own party and gave Lamont a powerful platform on which to run.

Lieberman’s 10,000-vote loss sets up a three-way race this fall among Lamont, Lieberman and Republican Alan Schlesinger, who has trailed far behind both Democrats in recent polls.

Though having both Lieberman and Lamont on the ballot could split the Democratic vote, Schlesinger is not considered a major threat. His campaign stumbled in July after revelations that he used a fake name to gamble at a Connecticut casino and had been sued over gambling debts at two New Jersey casinos.

Lieberman showed no signs of backing down, even though the Democrats’ withdrawal of support also means he will be starved of money from party sources to again take on the millionaire Lamont.

"The bottom line is that I’m definitely in," said the 64-year-old three-term senator and former vice presidential nominee. "While I consider myself a devoted Democrat, I am even more devoted to my state and my country."

It was Lieberman’s first loss in a Connecticut campaign since 1980, and he has long been one of Connecticut’s most popular Democrats. He became just the fourth Senate incumbent since 1980 to lose a primary.

Lamont won by hammering away at Lieberman’s support for the Iraq war and accusing him of being too close to Bush, repeatedly noting an incident in which Bush appeared to plant a kiss on the senator’s cheek after his 2005 State of the Union address.

Lamont’s campaign also was embraced by liberal bloggers, who saw it as a chance to take down an incumbent and play a bigger role in the Democratic Party.

White House spokesman Tony Snow called the primary "a defining moment for the Democratic Party, whose national leaders now have made it clear that if you disagree with the extreme left in their party they’re going to come after you."

A Quinnipiac University poll released in July showed that 51 percent of likely voters would support Lieberman in a three-way race, versus 27 percent for Lamont and 9 percent for Schlesinger, a lawyer who was formerly a legislator and mayor. However, a CBS News/New York Times exit poll of nearly 2,700 voters on Tuesday found that 61 percent said Lieberman should not run as an independent.

Lieberman said he fired his campaign manager and spokesman, and asked for the resignations of his campaign staff. He planned to hire two longtime aides as campaign manager and communications director, and to begin the search for a new pollster and media consultant.

"I do not blame my staff for my loss on Tuesday. I bear that responsibility," Lieberman said. "But now that we are entering a new and very different phase of the campaign, I wanted to bring in a new team."


Associated Press Special Correspondent David Espo contributed to this report from Washington.