Why did Democrats take a beating for passing a health care bill that was very similar in form to what Republican intellectuals had been urging for more than a decade? Because the Tea Party, conservative independents and Republicans have moved the political center to the right--marginally on a 0 to 100 scale, but enough to tip the scale away from Democrats. The electoral environment favors economic libertarians, and the Tea Party movement (or the conservative movement) has organized itself in such a way that really excites conservatives, while liberals, at a disadvantage ideologically (in the sense that conservatism has always been more organized and less diverse) cannot, as they did in 2008, build a tent around a larger coalition.
Holy hodgepodge of tendentious analogies, Batman!
The answer to why Democrats took a beating on HCR is actually quite simple. It's the same reason, in fact, that they took a beating on the stimulus and the bailouts.
They didn't listen to their base: liberals.
Liberals, not unions or minorities or women, are the engine of Democratic PR and campaign operations. They are the ones who send in letters to the editor and mount demonstrations and write on their shitty little blogs like this one. They're the ones who talk on cable news shows and fund commercials and 527s. They're the ones who get excited about politics and talk to their family and friends and argue Democratic policies and win converts.
Liberals by and large feel somewhere between disappointed and betrayed by the Obama Administration, and find their Senate delegation and its leader hopelessly gunshy. Despite Jonathan Chait et al.'s insistence that Barack Obama is "the most effective liberal president in at least four decades," it does not escape liberals that their president and massive, filibuster-proof majorities in Congress have so far given them Mitt Romney's health care plan, George W. Bush's tax cuts and bank bailouts, and were last seen working on Ronald Reagan's environmental regulation system. They are in general agreement that Barack Obama and Harry Reid gave away the store on health care with the public option. They worry that Obama screwed any liberal that will ever want to talk economics again by pushing a doomed stimulus plan that was less than half the size it needed to be, and nearly half of which was composed of inefficient tax cuts rather than public projects that keep people employed, giving the appearance of a Keynesian response but not enough oomph to sustain the recovery. They are sore that he wrote blank checks for Wall Street after its irresponsibility and craven behavior nearly destroyed the economy, but had no solution for putting people to work. They are outraged that he never fought for cramdown, and that his only attempt to deal with the housing market (HAMP) turned out to be not just unhelpful but downright predatory, cajoling people into staying in their homes just long enough for their lenders to squeeze a little more blood from their stones before evicting them anyway. And they are horrified by the Administration's war on whistleblowers, embrace of indefinite detentions, and decision to co-opt all of President Bush's illegal "war powers" rather than restore the Rule of Law.
And when they had the temerity to say something, the White House Press Secretary openly mocked them on national television. Mocked them, after all those hours and doors and phone calls and personal checks. Is there any other voting bloc in the country, any at all, that is ever openly derided by their own politicians?
Now we're a month and a half from the midterms and Democrats are wondering why they have no support, no volunteers, no campaign donations, and no one is applauding their policies on TV. It's a hell of a lot harder to motivate your base when they give you everything, and then two years later all you can say is, "at least I'm not the other guy, right?"