We can remember like it was yesterday the moment when the news came over the radio that Vice President Gore had chosen Senator Lieberman as his running made in 2000. There was an extraordinary thrill in the Jewish community that not only had a Jew been named to a national ticket but a particularly committed Jew. And there was a thrill among conservatives — and Reagan Democrats — at the prospect that Mr. Gore would campaign for the presidency on the centrist line that had won the highest office in the land for President Clinton and had won him reelection even as he was mired in scandal.

In the event, Mr. Gore veered to the left in his campaign, losing his shot at the presidency and going on from that defeat to a campaign to embitter and radicalize his party — against the war, against policies that would logically align with those seeking the survival of Israel, and against nearly everything that the man he’d picked as his running mate might be able to support. It has been tragic not only for him but for millions who had once been inspired by such Democrats as, say, John F. Kennedy, Hubert Humphrey, Henry M. “Scoop” Jackson, and Daniel Patrick Moynihan.

Tragic, too, for Senator Lieberman, who is now running well behind in the primary contest in which he is seeking the Democratic nomination for a fourth term. The latest polls suggest that the hard-left candidate, Ned Lamont, is likely to beat him over the issue of the war, and it is none too soon to start thinking about what will happen to Mr. Lieberman. We can’t help but think that the logical move for him is to embrace the Republican Party, possibly even seeking, come November, to run on its line in Connecticut.

Mr. Lieberman has ridiculed this idea. His campaign spokeswoman, Marion Steinfels, recently told the left-wing blog TPM Café that “He has said he’s always been a Democrat, and he’ll always be a Democrat.” So far, the senator says he would not accept the Republican nod even if that party nominated him. Ms. Steinfels told the blog, “Joe Lieberman will never run as a Republican. Never.” Then again, a cardinal rule of politics is to avoid saying “never.” There’s certainly a history of Democrats leaving their party when they concluded it no longer represented them. Just look at Phil Gramm’s decision to leave the Democratic fold in 1983 in part because the party’s leadership had punished him for working as a member of the House to pass President Reagan’s budget.

Senator Lieberman has endorsed such ideas as school choice and has opposed various quota programs. He has supported the notion that tax cuts can have economic benefits. He has continued, despite Enron, to aver the usefulness of stock options in the economy. On issues like abortion, his voting record has been as pro-choice as any liberal Democrat could wish, yet that has not prevented him from respecting members of the pro-life camp. Earlier this spring, he came to the defense of Catholic hospitals in Connecticut that were worried a state law might make them administer emergency contraception to rape victims in contravention of the hospitals’ religious beliefs.

For a party whose special interests increasingly take big-government, socialism, and abortion as a religion, Mr. Lieberman’s views were sure to engender fevered opposition. But Mr. Lieberman’s views on the war seem to have driven his party comrades crazy. His opinion boils down to this answer, delivered during a recent debate: “I believe it was the right thing for us to overthrow Saddam Hussein. I have been critical of the things that the administration did after that. But the fact is, we’re there now. And we have a choice. And that choice is between helping the Iraqis achieve a free and independent Iraq or abandoning them and letting the terrorists take over.”

Such is the state of the Democratic Party that such views have gotten Mr. Lieberman depicted in black-face. Even as Senator Clinton’s husband has campaigned on Mr. Lieberman’s behalf, Mrs. Clinton herself has been content to throw Mr. Lieberman under the bus, saying that she would support whoever wins the primary. Mr. Lieberman has suggested that were he to win the election as an independent, he would continue to caucus with the Democrats in the Senate. It’s hard to see why, though. If he loses this primary, it will be precisely because there is no longer room in the Democratic Party for views like those of Mr. Lieberman.