WASHINGTON — The political fate of Democratic Sen. Joe Lieberman will be on the line in Tuesday’s Democratic primary in Connecticut, an election that has become a referendum on the war in Iraq.

Lieberman, an all-out supporter of President Bush’s policies in Iraq, is being challenged by an anti-war political novice who is giving Lieberman — a three-term senator and his party’s vice presidential nominee in 2000 — a run for his political life.

If Lieberman loses, it would send a loud signal to other hawkish Democrats that the American public has become deeply disillusioned about the war and is going to hold them accountable at the polls.

Lieberman has threatened to run in November as an independent if he loses the Democratic primary.

Pollster John Zogby of Zogby International said his latest national poll in July showed only 35 percent of those surveyed said the war has been worth the loss of American lives. More than 2,500 American military personnel have been killed in Iraq.

The pompous senator has been called the White House’s favorite Democrat because of his unquestioning support for Bush’s militant policies. This stance puts him at odds with Democratic congressional leaders who only recently urged Bush to begin withdrawing troops from Iraq by the end of the year and to move on to a "more limited mission."

In a letter Monday to the president, a dozen key lawmakers including Sen. Harry Reid of Nevada — leader of Senate Democrats — and Rep. Nancy Pelosi of California — leader of House Democrats — told Bush that "the open-ended commitment in Iraq that you have embraced cannot and should not be sustained. We need to take a new direction."

The Democratic leaders are finally getting the message from rank-and-file voters who are far ahead of them in seeing the impact of the Iraqi quagmire on their lives and the nation.

Lieberman’s opponent in the Connecticut Democratic primary is Ned Lamont, a wealthy businessman. Most polls in the state show a close race.

Lieberman was former Vice President Al Gore’s running mate in the 2000 presidential race, but there appears to be no love lost between them now.

Gore opted to support former Vermont Gov. Howard Dean in the 2004 Democratic presidential primaries. Nor has Gore supported the beleaguered Lieberman this time around as he seeks reelection to the Senate.

Nevertheless, Lieberman — who once served as chairman of the moderate Democratic Leadership Council — has the backing of several centrist party leaders, including former President Bill Clinton, who campaigned for him, and his wife, Hillary, the senator from New York.

Although once criticized by Lieberman for his liaison with White House intern Monica Lewinsky, former President Clinton told a rally last month that the Connecticut senator is "a good man, a good Democrat, and he’ll do you proud."

The senator has voted with mainstream Democrats on many issues, including tax cuts, the environment, gun control and abortion rights. Like other mainstream Democrats, he supported the 2003 invasion of Iraq to seize Saddam Hussein’s weapons of mass destruction.

When those weapons turned out to be nonexistent and the death toll of American military personnel has continued to mount in the face of a tenacious insurgency, other mainstream Democrats began to question the war.

Not Lieberman. He wrote in The Wall Street Journal on Nov. 29, 2005: "I am disappointed by Democrats who are more focused on how President Bush took America into the war in Iraq almost three years ago and by Republicans who are more worried about whether the war will bring them down in next November’s elections, than they are about how we continue the progress in Iraq in the months and years ahead."

I hope there is a grand awakening for the senator when he learns that voters do care why we got into the war and, better still, how we can get out.