WASHINGTON -- Can a divided political party at war with itself attract enough popular support to win a majority in either house of Congress?

This is the rarely asked question that Democrats must confront in this election year on the issue of Iraq. It is an unshakeable political axiom that parties are successful when they are united behind a clear, compelling agenda. Yet Democrats are anything but united on Iraq, nor do they have a plan, beyond troop withdrawals, on what they would do to bring about a successful outcome there.

The latest evidence of the Democrats' uncivil war was in full view this week when former President Clinton, still the most popular figure in the Democratic Party, told its antiwar forces to cease their attempts to purge Democrats who support the war.

Clinton went to Waterbury, Conn., Monday to campaign for embattled Sen. Joe Lieberman, who is trailing anti-war insurgent Ned Lamont in the Democratic primary. Clinton campaigns for lots of Democrats, only in this case he was speaking up for a Democrat who is despised by his party's pacifist, anti-war forces because of his support for President Bush's war.

But Clinton's appearance at a packed rally in the Palace Theater had to do with more than just saving Lieberman from a looming defeat. It also had to do with his party's weakened posture on national security and fighting terrorism and, by proxy, with helping his wife, Sen. Hillary Clinton, who, like Lieberman, thinks the United States must continue to support the Iraqis in their struggle for democracy and is opposed to a withdrawal until that mission is accomplished.

Like other pro-war Democrats, Sen. Clinton has felt the wrath of anti-war activists who will be an obstacle to her ambitions to win the Democratic presidential nomination in 2008.

Bill Clinton does not mince words about what his party's now-dominant antiwar wing wants to do to any Democrat who supports the war -- calling the attempt by leftist ideologues like MoveOn.org to oust Lieberman "the nuttiest strategy I ever heard in my life."

"I think the Democrats are making a mistake to go after each other," he said earlier this month at a conference at the Aspen Institute -- lecturing his party's rank and file not to "allow our differences over what to do now in Iraq ... divide us instead of focusing on replacing Republicans."

Clinton is not the only Democrat chastising his party's left. Leon Panetta, Clinton's White House chief of staff, also took Democrats to task for going after Lieberman.

"The late Congressman Mo Udall used to say that when Democrats form a firing squad, they tend to form it in a circle and end up shooting each other," Panetta told me in an interview over the weekend.

"I'm a believer in Edmund Burke's philosophy that people elect you to exercise your conscience independently. They don't elect you to reflect whatever the popular will of the moment is," Panetta said. Continued...