I find it quite ironic that those best positioned to understand the implications of Lieberman's downfall are the most apt to describe the race as unimportant or meaningless instead of the momentus event it really is. I would throw into this TPM reader DK, who see this race as just one more D seat in the Senate.
It's not. You see, Capitol Hill is a small place, and it's a place where there's a certain incestuous cycle of staffers, lobbyists, journalists, and politicians. It's a community, with its own rules about who you can talk to, what can be said in polite company, and who you can bribe. There's a partisan divide, sure, but there's a much bigger divide between those on the inside of the Hill and those of us who aren't. We get our news from the New York Times, but they know the personalities involved and the real story. Many Dodd staffers were Lieberman staffers, and vice versa. Puncturing this bubble is a really big deal, because it changes how laws are passed.
Every bill that comes before the House and Senate faces a clear set of right-wing pressure points. The first and most powerful one is the Republican K-Street Project, which can whip all Republicans very quickly and effectively in the House, and nearly as quickly in the Senate. This is the machine that forces Republicans to obey the wishes of a right-wing leadership class, through the carrot of cushy corporate jobs and the stick of vicious primary challenges from the Club for Growth.
On the Democratic side, the pressure is just as intense, but more subtle. When a bill is introduced, a network of consultants, most of whom have corporate clients, begin to chatter about how taking a liberal position could weaken the Democratic Party. This is supplemented with a strong PR strategy by right-wing temporary coalition groups who put out networks of surrogates and ads to create a powerfully framed environment. Then business lobbyists come and visit Congressional offices, and make threats, attempt legislative bribes, or put out false but extremely persuasive pieces of information. There is often little real counterpressure, because liberal single issue groups have decided not to hold politicians accountable and do not cooperate with each other on issues not directly related to their vertical.
Within the Democratic party, resisting a bill is an exercise in holding the caucus together. The long minority status of the Democratic Party has allowed the development of bad faith actors within the caucus, who cut deals with right-wing groups and sabotage any possibility of resistance. Al Wynn is one such actor; Joe Lieberman is another. On key vote after key vote, these actors have sabotaged the progressive position through fake bipartisanship. It's no surprise that Lieberman's former chief of staff was a lobbyist for Enron; Lieberman himself is responsible for many of the corporate accounting scandals over the years because of his embrace of various financial lobbies.
One irony of the Lieberman race is that all the single-issue groups have endorsed Lieberman, and if you look at donations, so have the lobbyists. Indeed, this isn't a fight between 'the left' and 'the right' as it is traditionally defined, since no one would put NARAL on the right or even in the center. This is about creating a disincentive towards bad faith actors and corrupt lobbyists on the left.
The pervasive lack of accountability among Democrats is a real weakness for progressives, and the fact that there is some measure of accountability in the form of potential primary challenges means that there will be a behavioral change on the part of many members of Congress. No longer will they be able to listen to former staffers turned lobbyists, because they know that Lieberman's example could be their own. No longer can they take for granted their safety in safe districts, because Donna Edwards isn't the only principled and connected progressive around. And some of the tools and methodologies we're developing can be used to effectively damage Republican candidates, as we saw with the internet's mauling of George Allen after his macaca comments. Accountabiliy works all around.
The Lieberman challenge (and the Wynn and Lawless challenges) are about changing the revenue model of bad actors within the party and on the left and making it unprofitable to push a right-wing agenda. It's fairly clear at this point that Democrats will not take back either House without a progressive message, so getting rid of these bad actors actually helps a Democratic takeover. But more to the point, if Democrats do takeover a House of Congress, it's not like the right-wing pressure is going away. It's not like it's going to be easy to pass bills, since ripping New Dems and Blue Dogs from the leadership and having them be essential GOP caucus members is quite possible given the setup I've described. There should be an incentive system to discourage that kind of behavior. In fact there must be such an incentive system, or a Democratic Congress will simply be more competent at driving this country off a cliff.
So if you care about the Democratic Party being a functional opposition party, you should care tremendously about the Lieberman challenge. And if you care about the Democratic Party being a functional governing party that can get legislation passed, you'll care even more.