Glenn Greenwald's writing is among the best of those who actually understand how the Democrats managed to shoot themselves in the foot (or was it the head).
People are suffering economically and Democrats have done little about that. Beyond that, they failed to inspire their own voters to go to the polls. Therefore, they lost. By basing their power in Congress on Blue Dog dependence -- rather than advocating for the views of their own supporters and implementing those policies -- they failed, and failed resoundingly. Building their party around a large number of muddled, GOP-replicating corporatists not only creates a tepid and failed political image, but far worse, it prevents actual policies from being implemented that benefit large number of ordinary Americans. Democrats repeatedly refrained from advocating for such policies in deference to their Blue Dogs, failed to do much to alleviate the economic suffering of ordinary Americans, and thus got crushed. Anyone who thinks that Democrats lost because they were "too liberal" -- rather than because Americans are suffering so much economically -- is wildly out of touch, i.e., is a multi-millionaire cable TV personality who has spent decades wallowing in trite D.C. chatter.
The Republicans have long lived by what they call "The Buckley Rule": always support the furthest Right candidate who can plausibly win. This year, knowing that it would be a wave election, one that would sweep in huge numbers of Republicans in districts where they ordinarily couldn't get elected, they changed that to: support the furthest Right candidate, period. That's because they believe conservatism will work and want to advocate for it. Democrats don't do that. The DCCC constantly works to prop up the most "centrist" or conservative candidates -- i.e., corporatists -- on the ground that it's always better, more politically astute, to move to the Right. Even in the pro-Democratic wave years of 2006 and 2008, the Democratic Party blocked actual progressives and ensured that Blue Dogs were nominated, even though the anti-GOP sentiment was so strong that any Democrat, including progressives, could have won even in red districts (as Alan Grayson proved).
With that strategy, the Democratic Party now reaps what it has sown. Its message and identity are profoundly muddled, incoherent, unclear, uninspiring, and self-negating. Worse, its policies are mishmashes of inept half-measures that, with a handful of exceptions, produce little good for anyone (other than Wall Street, the Pentagon and other corporate interests). They are perceived as -- and are -- beholden to Wall Street, special interests, and the corporations they vowed to confront. They are without any ability to confront the massive unemployment crisis and financial decline the country faces. And as a result of all of that, they lay in shambles. Anyone who can survey all of that and cheer for the strategy which Democrats have been pursuing -- let's build our majorities by relying on GOP-replicating corporatist Blue Dogs -- or who thinks that this election loss happened because "Democrats are too liberal," resides in a world that has very little to do with reality. And that's true no matter how many times they repeat the simplistic snippets of exit polls to which they've obsessively attached themselves.