It should be obvious that if you foreclose on your voters, cut their pay, and legalize theft of their wealth by Wall Street oligarchs, they won’t be your voters anymore. Somehow, Democratic activists continue to operate as if policy doesn’t matter to voters, or that policy evaluation is a Chinese menu of different stuff, some of which you like and some of which you don’t, as in “Oh I’ll take a pro-choice moderate, with a bailout, and gay rights. And a Pepsi”. But that’s not how it works – voters’ lives get better, or they don’t. And under Obama, stuff has gotten worse. Obama’s economic policies have made economic inequality sharper than it was under Bush, due to his bailout of banks and concurrent elimination of the main source of wealth of most Americans, home equity. With these policy choices, Obama destroyed the Democratic Party and liberalism – under Obama’s first two years, the fastest growing demographic party label was “former Democrat.” Liberalism demands that people pay for a government, but why should anyone want to pay taxes for the terrible governance Obama has implemented?I disagree that Obama's governance has been "terrible" -- and it's a stretch to say he "destroyed" the Democratic Party. But it's hard to argue that he's been good for Democrats.
In addition to losing the House, Party ID is down quite a bit since 2008.