Through a quirk in the rules, Connecticut Sen. Joe Lieberman may once again emerge as the Senate Democrats' indispensable man, despite his support of the Iraq war, his full-throated endorsement of Republican Sen. John McCain for president and his prime-time speaking slot at the Republican National Convention in September.
The Democrat-turned-independent, who provided the crucial 51st vote to give Democrats control of the Senate in 2006 could - a number of election forecasters project - provide the crucial 60th vote party strategists are lusting for to build a "filibuster-proof" Senate majority after Nov. 4.
Some scoff at the idea, amid reports that Senate Democratic leaders have already decided to strip Mr. Lieberman of his chairmanship of the Senate Homeland Security and Governmental Affairs Committee in the new Congress, when the Democrats are almost universally expected to pad their majority. The skeptics say Mr. Lieberman burned too many bridges in the past year with his ties to Mr. McCain, who reportedly wanted to pick the Connecticut lawmaker as his vice-presidential running mate.
But others say the numbers will force Senate Majority Leader Harry Reid, Nevada Democrat, to think again.
Mr. Lieberman "has been all but written off as a political force, but he just might rise from the dead," said Kenneth Dautrich, who teaches public policy at the University of Connecticut and founded the university's Center for Survey Research and Analysis, in a phone interview.
"Depending on how the vote goes, he could be the most marginalized man in the Senate or once again one of its most important," Mr. Dautrich said.
Currently, there are 49 Democrats and 49 Republicans in the Senate, with Mr. Lieberman and fellow independent Vermont Sen. Bernard Sanders voting with the Democrats to give the party a 51-49 majority. Had Mr. Lieberman switched sides, Vice President Dick Cheney would have been summoned to break the 50-50 tie and Mr. Reid would have instantly become the Senate minority leader.
With Democrats surging in the polls, many see the party coming up just short of the 60-vote total - the number needed under Senate rules to close off debate and force votes on stalled legislation. If the Democrats get to 58 or 59 seats, Mr. Lieberman - at least in theory - holds the deciding vote once again.
Mr. Lieberman "may be more relevant than ever," Mr. Dautrich said.
Vice President Al Gore's running mate on the 2000 Democratic ticket, Mr. Lieberman broke sharply with the party over his strong backing of the Bush administration on the Iraq war and the larger war on terrorism.
He won a fourth term to the Senate in 2006 running as an "independent Democrat" after losing the Democratic primary to a little-known challenger running on an antiwar platform.
Mr. Lieberman has deflected speculation on his Senate future while campaigning vigorously for Mr. McCain. Asked by an ABC television affiliate in Florida in an interview this week about the filibuster possibilities, he said, "I will do what independents are supposed to do, not just what the Democratic Party tells you to do."
James W. Pindell, editor of the Internet-based newsletter Politicker.com, argued that Mr. Lieberman's vote will be far less valuable in the new Senate, since filibuster votes rarely break down along strict party lines the way votes for party control of the chamber do. If Mr. Lieberman defects, he said, it is likely there will be a few moderate Republicans who could be drafted to end the filibuster.
"And when it comes to a long list of issues - abortion, environmental policy, energy policy, tax policy - it is hard to imagine Lieberman walking away from a career pattern of votes just because he is upset with the Democratic leadership," Mr. Pindell said.
"Lieberman can be a threat on some votes [to defect], but he is no different than any other senator on the fence," he added.
Mr. Lieberman has a mixed record on supporting the Democratic majority on cloture votes in the current Congress. He voted to support a Republican-led filibuster blocking votes to end the war in Iraq and to censure former Attorney General Alberto R. Gonzales, but voted to end a filibuster on a major overhaul of immigration laws.
But Mr. Dautrich said Mr. Lieberman could have real leverage in a potential Obama administration on high-profile votes such as health care reform or Supreme Court nominees, where the filibuster threat gives the minority party real bargaining power.
Nevada Sen. John Ensign, head of the National Republican Senatorial Committee, said in an interview on MSNBC Monday the Republican Party would welcome Mr. Lieberman "with open arms" if the Democrats spurn him.
Mr. Ensign conceded there was a "fair possibility" the Democrats will get or come close to the magic 60-vote total.
"Joe is certainly going to be a wild card in there," he said.