After reading about Joe "I've given my word I will caucus with Democrats" Lieberman threatening to switch parties and potentially throw control of the Senate to Republicans, I had a thought: Would it really be that big a deal? I ask this question out of my loyalty to the progressive movement and the Democratic Party - not out of ideological purity or my disgust for Lieberman as an individual (even though that disgust does exist). Before you scream "YES IT REALLY WOULD BE A BIG DEAL," just hear me out.
Democrats control the House, and as we've seen on the Iraq debate, a narrow majority in the Senate effectively stops that institution from doing anything. Thus, we have basic gridlock right now. Additionally, most believe that President Bush will veto any good legislation that manages to get out of Congress right now - meaning this gridlock is extra guaranteed by the White House. Throwing the Senate to the Republicans by one vote (which, by the way, a Lieberman switch would not necessarily accomplish, thanks to gray areas in Senate rules) wouldn't change this gridlocked situation at all. Democrats would still have the House and filibuster-ready Senators to stop anything awful from getting to Bush's desk. Meanwhile, Democrats would still have investigatory/oversight power from their House chairmen.
What about things like judicial nominations that only the Senate deals with? I share a tiny bit of concern, in that I worry about Senate Democrats intenstinal fortitude in using the filibuster. Then again, Senate Democrats would only have to filibuster for the next year and a half until we have a new president - and that's not much to ask.
The politics of the situation would be terrific for Democrats (even though you can bet that many Senate Democrats will do whatever they can to keep their majority perks, even if it means selling the entire progressive agenda and the 2006 election mandate down the river - what's personally awesome for individual Democratic senators and their egos' desire to be called "chairman" isn't necessarily good for the long-term prospects of the Democratic Party as a whole). They could pass their entire agenda through the House and then blame the Republican Party in the Senate and White House for stopping it (remember how the GOP used Jeffords' switch to rev up its steamroller with the viciously effective attacks of "obstructionism" in 2002?) This is especially advantageous because the 2008 Senate races look quite favorable to Democrats, meaning they have a good shot of taking back the upper chamber by way more than the one vote Lieberman represents.
My guess is that Lieberman understands this, that he's not really going to switch, and that he's just going to periodically tell people he "might" switch whenever he feels he hasn't been given enough love by Beltway reporters. The man is, at his core, the biggest narcissist in contemporary congressional history. What motivates him more than anything is seeing himself on television. If that means backing out of his own promises and threatening to overturn a national election in order to send more troops to die in a war, then he's willing to do that. However, he knows that once he turns the threat into reality and switches, he immediately will be perceived as politically irrelevant and, because he will have switched in defense of the Iraq War, he will also likely remembered as the most hated and infamous U.S. Senator since Joe McCarthy.
So, to sum up: I hope Lieberman switches because A) it would be advantageous for Democrats in the long-term B) it wouldn't hurt Democrats or progressives in the short-term, if Senate Democrats developed the spine to filibuster horrible nominees (admittedly an "if") and C) while he already is politically irrelevant in terms of actual power, Lieberman's switch would, finally, make him widely perceived as irrelevant, meaning that he would cease to have any effect on the national debate and that his melting, Emperor-from-Star-Wars face would stop appearing on my television set and freaking out my dog, Monty.