Sen. Joe Lieberman's staunch stay-the-course defense of President Bush's Iraq policies isn't winning him any friends among fellow Democrats.

Lieberman's pro-war views may be winning him praise from a grateful White House, but some Democratic colleagues see him as undercutting their party's efforts to wrest control of Congress from the GOP next fall.

"He's doing damage to the ability of Democrats to wage a national campaign," said Ken Dautrich, a University of Connecticut public policy professor. "It's Lieberman being Lieberman. And it's frustrating for people trying to put a Democratic strategy together."

Sensing political vulnerability in Bush's handling of Iraq, Democrats are anxious to craft a compelling anti-war theme uniting the party for the pivotal midterm congressional elections.

Democrats hope a surging anti-war tide in 2006 can help them shatter the GOP's 12-year lock on the House and win back the Senate for the first time since 2001.

"It's not a tidal wave now, but the ingredients are starting to fall into place," said veteran Democratic strategist Tad Devine.

Lieberman, who seems to relish his role as a maverick, is veering far from the Democratic script. His vocal support for the war, a stark and frequent reminder of the deep divisions among Democrats on how to end the war, makes him something of a marked man.

"Lieberman is a big voice, he was Al Gore's running mate and he carries weight," said Dautrich. "But he beats to his own drum and that's a problem for Democrats."

Lieberman's pro-Bush stance has long rankled many Democrats, but his comments Tuesday scolding anti-war critics within his own party had a sharper edge.

"It is time for Democrats who distrust President Bush to acknowledge that he will be commander in chief for three more critical years, and that in matters of war we undermine presidential credibility at our nation's peril," said Lieberman, urging bipartisan cooperation.

The words drew a frosty response from Democratic National Committee Chairman Howard Dean, a former Lieberman foe during the 2004 presidential primaries.

"We believe that talking about the president's failed strategy in Iraq is not unpatriotic," Dean said on CNN. "It may undercut the president, but it does not undercut our troops."

Dean tossed a parting jab at Lieberman, claiming Democrats are not as divided on Iraq as press reports say. "The differences are pretty small, perhaps, Senator Lieberman excepted," he said.

The senator has a long history of bucking his party. He was one of the few Democrats to chide former President Clinton during the Monica Lewinsky scandal. He has assailed Democrat-friendly Hollywood for producing sleaze.

Lieberman, a firm backer of U.S. intervention in Iraq, voted for the 1991 Gulf War, casting the fight in moral terms.

"They may not agree with him, but Democrats respect what he is saying," said former Clinton White House spokesman Michael McCurry. "People know he's not playing politics with Iraq."

The Bush Administration, meanwhile, can't seem to get enough of the senator who has sided with the president on many foreign policy, defense and homeland security issues.

Lieberman huddled with Defense Secretary Donald Rumsfeld at a private Pentagon breakfast meeting Thursday amid rumors he could be a potential Rumsfeld successor.

Bush singled out Lieberman for praise in his two most recent speeches, including Wednesday in New York where he noted: "Senator Lieberman is right."

Last month, as partisan debate raged, Bush cited "fine Democrats like Senator Joe Lieberman" who oppose immediate troop withdrawals.

Some say Lieberman may be filling the void left by Rep. Jack Murtha, a hawkish Pennsylvania Democrat and longtime GOP favorite until his dramatic call last month for a speedy troop withdrawal from Iraq.

Lieberman's pro-war views may not be as popular in Connecticut where former Gov. Lowell Weicker has suggested he may run against the senator unless a major anti-war challenger surfaces. Dean's brother Jim, who heads the liberal advocacy group Democracy for America, is rallying anti-Lieberman forces in Connecticut as well.