“Stay the course — that’s not a winning strategy in Iraq and it’s not a winning strategy for America,” declared anti-war candidate Ned Lamont as he accepted the Democratic nomination for the U.S. Senate from Connecticut.

The man Lamont beat, Senator Joe Lieberman, conceded defeat in the Senate primary Tuesday night. But the three-term incumbent announced he would go ahead with a sore-loser campaign on a third-party line against the candidate of the party that nominated him for vice president in 2000.

“I will not let that result stand,” Lieberman said of the decision of Connecticut Democrats to hand their party’s nomination to Lamont, a political unknown before his frustration with Lieberman’s support of the war in Iraq led him to challenge the Bush administration’s favorite Democrat.

“We’ve just finished the first half, and the Lamont team is ahead,” the senator told supporters gathered at a Hartford hotel. But the senator claimed “our team… is going to surge forward to victory in November.”

With 97 percent of the state’s precincts reporting in the most closely watched Senate primary the nation has seen in years, Lamont had 52 percent, while three-term incumbent Lieberman trailed with 48 percent.

Turnout was high in the primary, especially in areas that were friendly to Lamont. But the challenger’s margin was not enough to discourage the senator from running on his “Connecticut for Lieberman” line in a fall race that will also include Republican Alan Schlesinger.

It is expected that Lieberman will try to paint Lamont as a one-issue candidate, and there is no question that an anti-war message defined Lamont primary campaign.

But, as he declared victory, Lamont painted himself as a reformer who would seek not just to change U.S. foreign policy but to reorder national priorities — particularly on issues such as health care and education.

Saying that Connecticut “voted for big change,” the primary winner told his cheering backers, “It’s time to fix Congress.”

To Lamont’s view, that fix requires opposing the Bush White House — something Joe Lieberman refused to do on the most fundamental issues of the day. That failure cost Lieberman his party’s nomination Tuesday, and could yet cost him his Senate seat.