Ned Lamont's primary victory over Joe Lieberman may turn out to be a key moment in stopping the Bush Administration's destructive policies. But that depends on what the rest of us do.

Lieberman, as a majority of Connecticut's Democratic voters just acknowledged, was Bush's fiercest Democratic ally, not just on the Iraqi war, but on issues from the bankruptcy bill to his regressive energy bill, tax plans, and judicial nominations, not to mention Terri Schaivo. The question now is whether Lieberman can hold his seat through a divisive third party run. Citizens throughout the country can play a crucial role by pressuring key elected leaders and organizations that initially supported him to switch their support. Some of this has already begun to occur, with Harry Reid and Chuck Schumer's strong statements that the Democratic Senatorial Campaign Committee will fully back Lamont, and Hillary Clinton's donation of $5,000 from her PAC. But the process needs to be taken still further.

Though Lieberman's announced that he'll run as a third party candidate, that isn't set in stone. His chances of splitting the party enough to win in November or elect a Republican depend on the support he lines up. If it's only from major corporate and Republican interests, many of whom contributed to his primary campaign, then voters are far more likely to see him as merely a Republican stalking horse. According to ABC's George Stephanopolous, a close Lieberman advisor said that Karl Rove has already approached his campaign and offered to help. What got Lieberman as close as he came was the legitimacy that he gained from the backing of key Democratic leaders like Schumer, Bill Clinton, Chris Dodd, Barbara Boxer, and Barack Obama, and from institutions like the Connecticut AFL-CIO (though the state's major teachers unions and the Machinists union backed Lamont), and from Planned Parenthood, NARAL, the League of Conservation Voters, and the Human Rights Campaign. They supported him, I believe, because of old friendships and allegiances, because they didn't expect Lamont to emerge as such a powerful candidate or his insurgent campaign to touch such a nerve, and because there's a standard (and problematic) assumption that if an incumbent is at least somewhat on your side, you give them your automatic backing even if their opponent is as strong on the relevant issues or stronger. So National Abortion Rights Action League backed Lieberman despite his immensely disturbing position that a hospital could refuse emergency contraceptives to a rape victim and despite his playing a key role, by blocking any filibuster, in the confirmation of the profoundly anti-choice Justices Roberts and Alito (who have also been as ghastly as expected on environmental, social justice and civil liberties issues). It was the support of institutions and individuals like these that gave Lieberman his veneer of moderation.

Now, we face a different situation. If anyone who loses a party primary, even a close one, can simply run on their own, then primaries become meaningless as ways to democratically elect our leaders. Lamont stressed from the beginning that he would support Lieberman if he lost and even campaign with him. Lieberman needs to do the same. The 40 percent statewide turnout was nearly double the last major contested statewide Democratic primary, a dozen years ago. Given that Connecticut's Democratic voters have spoken, Lieberman needs to respect their will, and not split the party by refusing to accept the will of the voters.

So the challenge is to line up every possible aspect of Democratic and organizational support behind Lamont-and to strip Lieberman of the resources and support that got him as close as he came. The initial shifts of high-profile Democrats are encouraging. But we need to ask more of them. Their endorsing Lamont matters, as do their financial contributions. But particularly for those who gave Lieberman credibility by initially backing and campaigning for him, that's not enough. They need to make clear that they will visibly and energetically campaign for Lamont as the legitimately elected representative of their party, and follow through on this commitment if they can't convince Lieberman to withdraw. It's up to all of us as to make sure the Democratic leaders who represent us respond.

The same thing's true with liberal organizations that endorsed Lieberman when Lamont's campaign had yet to coalesce. If we're members or supporters, we need to personally contact them and ask that they back Lamont and not Lieberman in this next round. They need to recognize that supporting Lieberman at this point means supporting the Bush administration, and everything it stands for.

We might remember that this isn't the first time Lieberman has placed his career above loyalty to party and beliefs. He also hedged his bets in the 2000 election, by running for reelection as Connecticut Senator while also running for Vice President. It didn't help the ticket, but worse yet, had Gore won (as he would have without the Florida machinations), Lieberman would have had to resign his Senate seat, and be replaced by a Republican appointed by Republican Governor John Rowland. So Lieberman has a long history of looking out only for himself, and we might also do our best to ensure that the media remembers this.

If we're successful enough in our efforts, the wells of support for Lieberman may dry up sufficiently that he'll decide not to make a serious third-party race. Or we'll help Lamont gain enough support and momentum to solidly win. Contributing to Lamont's campaign is important-money matters. But wherever we live, we now have another task. That's to raise our voices enough with the elected officials and organizations that represent us, so that this campaign indeed can indeed become a potential national turning point.

Paul Rogat Loeb is the author of The Impossible Will Take a Little While: A Citizen's Guide to Hope in a Time of Fear, winner of the 2005 Nautilus Award for the best book on social change, and Soul of a Citizen See