Joe Lieberman, Democratic Survivor

Nothing is official yet, but the momentum seems to be on Joe Lieberman’s side in his bid to retain his chairmanship of the Senate Homeland Security and Governmental Affairs Committee.

Needless to say, this is a distressing development for Lieberman’s many passionate critics on the left, who believed that his fervent support of John McCain — and occasional elbow in Barack Obama’s face — combined with the Democrats’ beefed-up Senate majority would be enough for the party’s caucus to jettison him once and for all.

But that’s not how things have played out since last week’s election — and it really shouldn’t come as a surprise.

The Lieberman saga began, of course, after the 2006 elections, when Senate Democrats, locked out of the majority for all but 16 months of the previous 12 years, found themselves with 49 seats. The chamber’s two independents, Lieberman and Vermont’s Bernie Sanders, were needed to put them in control — and Sanders, who insisted on retaining his independent status while reliably siding with Democrats, wasn’t really an issue.

But Lieberman was. Back in those days, he was embittered by his party’s abandonment in that fall’s Connecticut Senate race and emboldened by the comfortable victory he nonetheless racked up as an independent. Returning to Washington after his home-state triumph, he seemed intent on poking a stick in the eyes of all of his Democratic tormenters. Needing his vote, Senate Democrats had no choice but to abide him.

So it was that Lieberman, declaring himself an independent Democrat (as opposed to his campaign season pledge to return to the Democratic fold), was handed the Homeland Security gavel anyway in January 2007. Then he began settling scores, bluntly attacking his party and its leaders for their posture on Iraq and other national security issues and hinting that he’d be open to backing a Republican presidential candidate in 2008.

Some on the left shouted for Democrats to cut Lieberman loose on the spot, citing an agreement that Majority Leader Harry Reid had worked out after the ’06 election with G.O.P. leader Mitch McConnell that didn’t provide for control of the chamber to change partisan hands if Lieberman — or any other senator — switched allegiances to the G.O.P. Reid and his colleagues resisted, though, in part because the agreement with McConnell was a technicality: In practice, had Lieberman declared himself a Republican, the G.O.P. would have howled (to considerable effect) that Democrats were clinging to fine print in an effort to rule the chamber from a minority position.

By the end of 2007, Lieberman formally endorsed John McCain, whose G.O.P. primary campaign was in the beginning stages of its revival at the time, and began touring the country at his side. As it became clear that McCain would secure the Republican nomination and face Obama in the fall, Lieberman’s visibility increased, with McCain strategists seeing him as the perfect ambassador to independent voters.

McCain’s primary-season triumph also introduced the possibility that Lieberman might be asked to serve as his running mate, a development that would have made him the first person ever to serve on the national ticket of both major parties. Lieberman was publicly dismissive of such talk (as all good would-be VPs are), but his moves telegraphed genuine interest. McCain, it became clear over the summer, was just as excited by the idea.

As this vice presidential intrigue was building steam, something else was becoming clear: The Democrats were going to be in better — much better — position in the Senate come 2009. By this past spring, Democrats were beginning to dream of a 60-seat majority. Not a single Democratic incumbent appeared to be in danger, while Republicans in some of the deepest red states were fighting for their lives, swimming against an anti-G.O.P. Congressional tide every bit as strong as the one in 2006.

These two developments — McCain’s desire to put Lieberman on the G.O.P. ticket and the Democrats’ overpowering strength at the Senate level — put Lieberman in a tricky spot. To mollify a skeptical G.O.P. base and secure McCain’s VP slot, he’d need to ratchet up his attacks on Obama and begin distancing himself from some of his more liberal views, particularly on social issues. But the harsher his attacks on Obama, the worse position he’d be in to bargain with Senate Democrats if he had to return to the chamber after the election.

Lieberman tried to preserve both options. In the spring and summer months, as his VP prospects seemed to brighten, he launched a series of sharp and widely reported attacks on Obama.

“If we did what Senator Obama wanted us to do last year, Al Qaeda and Iran would be in control of Iraq today. The whole Middle East would be in turmoil and American security and credibility would be jeopardized,” he said in one Fox News appearance.

After Obama appeared at the AIPAC conference the day after clinching the Democratic nomination in June, Lieberman held a conference call in which he questioned Obama’s commitment to Israel and his understanding of Iran. That led Obama to personally confront Lieberman on the Senate floor. When it became clear that Lieberman would speak at the Republican convention, he seemed on course for an irrevocable split with his fellow Democrats.

But then he cooled off. The reason: Conservative activists and Republican establishment figures, many of them eager to secure the No. 2 slot for Mitt Romney (to position him for a future White House run) launched a campaign to deny Lieberman a spot on McCain’s ticket. McCain tried to fight it (he noticeably burnished his own anti-abortion credentials over the summer) but ultimately gave in, opting instead for Sarah Palin.

That, in turn, led Lieberman to pivot. Had he been tapped for the G.O.P. ticket, he would have been all-in with McCain, ready to burn all of his bridges with Democrats in the fall campaign in an effort to win the White House. His sharp spring and summer rhetoric would have been a mere preview of his general-election assault against his old party and its candidate. But after McCain snubbed him, Lieberman was forced to consider his future in the Senate — and the reality that Democrats would be its dominant party after the election, and probably for years to come. So, instead of shredding Obama, he switched gears and began instead focused on talking up McCain. His much-anticipated G.O.P. convention speech, for instance, was devoid of red meat (and just about any mentions of Obama, for that matter) and put much of the audience to sleep. A VP nominee Lieberman, no doubt, would have delivered a much sharper address.

Lieberman, clearly, was thinking ahead to life in the Senate. He stuck by McCain through the fall, but mostly resisted lashing out against Obama. (It could have been much worse.) At the same time, he continued voting with Democrats on most issues outside of foreign policy.

As a result, the campaign ended last week with Senate Democrats in a forgiving mood, even if the party’s grass roots still want blood. Most Democrats in Washington are happy to have Lieberman aboard for most Senate votes — especially with the party now so close to a filibuster-proof 60 votes — and wouldn’t be inclined to move against him just because he endorsed a losing presidential candidate. They needed more motivation than that, and by reining himself in this fall, Lieberman didn’t provide it.

Joe Lieberman, Democratic Survivor