Tweaking some famous rock lyrics by The Clash:

What I really want to know,
Should he stay or should he go?

I am referring to the question of whether Joe should go. As in, Joe Lieberman. As in, Joe Lieberman the lifelong Democrat-turned-independent who caucuses with the Senate Democrats, but who spent most of 2008 attacking Barack Obama on behalf of his friend John McCain. As in, the selfsame Joe Lieberman who spoke at the Republican National Convention, impugned Obama's patriotism, and spread deceptive half-truths about Obama's purported lack of support for the troops.

And even after compiling this track record, Lieberman apparently finds its outrageous that the Senate Democrats might deem it appropriate, in their caucus meeting tomorrow, to discipline him via secret ballot...perhaps by taking away his chairmanship of the crucial Homeland Security and Government Operations Committee; or knocking him down a few rungs on the seniority ladder; or booting him off the Armed Services Committee.

Lieberman - clearly firm in his belief that actions should not have consequences, that he should incur no penalty for palling around with the McCain forces - is now threatening in so many words to defect to the Senate GOP if the Democrats try to snatch away his Homeland Security gavel. Well, perhaps the Democrats should call Lieberman's bluff on that one, just to see whether he is really serious about spending the remaining four years of his term as a member of the minority party.

And even if Lieberman does walk - leaving the Democrats with, say, a bumper crop of 57 or 58 senators - the majority party at least will have taken a stand on an important principle: the notion that loyalty matters, that certain partisan borders cannot be breached.

Remember four years ago, when Democratic candidate John Kerry tried to lure McCain away from the GOP camp? If McCain had endorsed Kerry in a losing cause and then sought to reclaim his Republican Senate chairmanships in 2005, the Senate GOP majority would have enforced party discipline by smacking him down, and none of us would have imagined they'd ever do otherwise.

Democrats are more...shall we say...contemplative about such things, judging by the reports that some senators would like to see Lieberman slapped on the wrist and nothing more. Some Lieberman defenders in the press insist that the Senate Democrats, by lowering the hammer on Joe, would be signaling their intolerance for mavericks and centrists, and that, in fact, the Senate Democrats would be violating Barack Obama's post-election call for a new bipartisan spirit. But the problem with this argument is self-evident; a number of Democratic senators are centrist or even conservative - among them, Ben Nelson of Nebraska, Max Baucus of Montana, Brian Dorgan of North Dakota, and Ken Salazar of Colorado - and they're respected and accepted by their party peers. Lieberman is different. He flagrantly crossed the line.

Actually, he did more than cross the line. He stayed silent as the Republican running mates recited lies virtually every day about Obama's proposals (notably on taxes), and sometimes he personally fanned the flames. When asked last April 14 whether Obama is "a Marxist, as (conservative commentator) Bill Kristol says might be the case," Lieberman replied: "Well, you know, I must say that's a good question." On Oct. 23, Lieberman said that Obama wants to practice "what used to be known as socialist theory." At another point in the campaign, Lieberman declared that, while McCain always put "country first," Obama did not.

And, during his GOP convention speech, Lieberman recited the standard GOP line about how the Democratic candidate is a military wimp who doesn't care about the troops. The key passage: "When others wanted to retreat in defeat from the field of battle, which would've been a disaster for the U.S.A. — when colleagues like Barack Obama were voting to cut off funding for our American troops on the battlefield — John McCain had the courage to stand against the tide of public opinion..." (Italics are mine.)

Lieberman, who now wants to retain all his Democratic-bestowed perks, stood at the Republican convention podium and uttered a classic half-truth right from the Karl Rove playbook. On May 24, 2007, Obama voted against a particular troop-funding bill because it didn't contain any provisions for bringing the troops home from Iraq; as Obama stated at the time, "We must fund our troops, but we owe them something more. We owe them a clear, prudent plan to relieve them of the burden of policing someone else's civil war." In other words, he didn't like the strings that were attached; he didn't want to tie his support for the troops to President Bush's status quo strategy.

The irony of Lieberman's attack on Obama was that he too had recently voted to "cut off funding for the troops." On April 26, 2007, Lieberman voted with virtually all the Senate Republicans in opposition to a different troop funding measure, because they didn't like the strings that were attached. This particular bill decreed that Bush would get his troop money, but only if he began troop withdrawals. The bottom line: Lieberman had his own reasons for voting no on troop funding - just as Obama, one month later, had his own reasons for voting no on troop funding.

And Lieberman's transgressions appear particularly egregious when one considers his own history with Obama. In March 2006, when pro-war Lieberman faced an antiwar challenger in Connecticut's Senate Democratic primary, he asked Obama to come east and help save his hide. And Obama did so, stumping for Lieberman in Connecticut. Yet here was Lieberman, in April 2008, paying Obama back by suggesting on national television that Obama might be a Marxist.

The bottom line: Lieberman is a special case. He has set himself up to be seriously disciplined by the Democrats, just as three southern House Democrats were stripped of their seniority during the '60s when they actively worked against the party's presidential nominees. Precedent, in other words, dictates that the Senate Democrats take some kind of action, if only to demonstrate to their grassroots supporters that the party stands for something, that multiple acts of betrayal should not be countenanced.