Washington ? Back in 1962, when Sen. Joseph Lieberman was 20, he attended a raucous Democratic state convention in Hartford. Abraham Ribicoff, the former governor, had decided to leave his post in the Kennedy Cabinet to run for the Senate.

John M. Bailey, then the party chairman, wanted to clear the field for Ribicoff, his protege, but the Democratic congressman at large, Frank Kowalski, had his own eyes on the Senate nomination.

Bailey easily mustered the convention votes to endorse Ribicoff, and then turned around to offer Kowalski another shot at his old job in Congress. Kowalski, on a high horse, refused, and briefly the prospect loomed of a Democratic ticket without a Polish name – a no-no in an era of ethnically balanced politics.

The other day, Lieberman recalled what happened next: “Backstage, the call went out for a Polish Catholic, preferably someone who could speak Polish.” The answer was a lawyer named Bernard Grabowski, who had no idea that morning that he was about to become a candidate. In November, Grabowski was elected.

Jump forward to May 2006, another Democratic state convention and another challenge to a party favorite, Lieberman. Wealthy businessman and one-time town official Ned Lamont, a critic of Lieberman’s support of the Iraq War, musters one-third of the votes. But since 1970, Connecticut has offered a primary to candidates who can garner even 15 percent of convention support, so the Lamont-Lieberman battle goes on to a showdown on the awkward date of Aug. 8.

In an interview, Lieberman sounded a note of nostalgia for the old days. “John Bailey genuinely believed that primaries were not only divisive but often didn’t pass the ultimate test of finding the candidate who could win,” he said. If Bailey were alive, his attitude would be, “We have an incumbent senator who is quite popular in the state; we have an opportunity to elect three Democratic congressional challengers; we have a very tough race for governor. Why would we want to challenge an incumbent senator who could lead the other candidates to victory?”

The answer is simple: the war, which has lost support among Connecticut voters, especially those likely to vote in a Democratic primary in the heart of summer-vacation season. Lieberman says he is not surprised.

“I didn’t know who the challenger would be, but I felt there was a very good possibility this would happen,” he said. “I told people at my fundraisers last year there could well be a challenge from the left of the party. In 2003 and 2004, when I was visiting the primary states (running for the presidential nomination) I saw the growing intensity of the feeling about the war. So, if I was not surprised, you might ask why I didn’t alter my position.

“I think we did the right thing in overthrowing Saddam and I think we are safer as a result,” he continued. “Second, while I have been very critical of the Bush foreign policy before the war and the Rumsfeld-Bush policies in Iraq after Saddam was overthrown, I also made a judgment I would not invoke partisan politics on this war.”

That was the point of a Wall Street Journal op-ed piece Lieberman wrote last November, endorsing the president’s announced strategy to defeat the insurgency and establish a democratic government in Iraq. That article infuriated Lamont and launched his candidacy. “It was decisive,” Lamont told me in an interview. “Lieberman suggested that the critics were undermining the credibility of the president. I thought he was wrong.”

“My opponent says it broke Democratic unity,” Lieberman said. “Well, dammit, I wasn’t thinking about Democratic unity. It was a moment to put the national interest above partisan interest.”

Sources in Connecticut tell me that momentum in the campaign is mostly with Lamont. Lieberman insists he can win the primary. But he has another option. Connecticut law says that he could run as an independent, but he would have to file 7,500 signatures the day after the primary.

He says he knows of no effort to gather signatures now. But he also says, “I want to put my whole record before the whole voting population of Connecticut” – clearly implying an independent run if he loses to Lamont in August.

Thus, a possibility John Bailey could not have imagined: A former Democratic vice presidential candidate, a three-term senator, a former state Senate majority leader and state attorney general forced to run as an independent.

“I know I’m taking a position that is not popular within the party,” Lieberman said, “but that is a challenge for the party – whether it will accept diversity of opinion or is on a kind of crusade or jihad of its own to have everybody toe the line. No successful political party has ever done that.”