"Democrats ought to stand back and ask themselves the most important question: Does Joe Lieberman vote his conscience or is he controlled by one interest group or another? I think the answer is clear. He votes his conscience, and I don't think he ought to be penalized (by Democrats) for that," he said.

Last week's Quinnipiac University primary poll showed him trailing Lamont by 4 points (within the poll's margin of error), 51 percent to 47 percent.

However, while Lieberman has infuriated his party's antiwar activists, it seems Connecticut's electorate at large supports him. A second poll showed him winning in a walk in the November election.

"Lieberman is still strong among Republicans and independents, and that's why he wins in a three-way race if he runs as an independent in the general election," said Doug Schwartz, Quinnipiac's poll director. "In that situation, Lieberman polls 51 percent to 27 percent over Lamont among registered voters, with Republican attorney Alan Schlesinger at 9 percent."

Still, if Lamont defeats Lieberman in the primary, it would surely send an intimidating warning to Democratic lawmakers that anyone who dares to vote their own consciences will do so at their political peril. It would drive a deeper wedge in the party on the war and, arguably, further weaken its already anemic posture on national security in the era of global terrorism.

This is already happening in Washington state, where Democratic Sen. Maria Cantwell, who has been booed at party events over her opposition to an immediate pullout, has begun to soften her position. She, too, faces antiwar opponents to her re-election.

Some aren't cowed by the antiwar threats of political retribution. Sens. Barbara Boxer and Joe Biden are campaigning for Lieberman. But if he goes down to defeat next month, it will further divide his party on the most vital national-security issue of our time.