And the depth of the revolt against Obama has been striking too. As near as I can tell, there's a small but significant minority who are so enraged that they'd be perfectly happy to see his presidency destroyed as a kind of warning to future Democrats. It's extraordinarily self-destructive behavior — and typically liberal, unfortunately. Just ask LBJ, Jimmy Carter, and Bill Clinton. And then ask them whether liberal revolt, in the end, strengthened liberalism or conservatism.
Smart politics often involves keeping an eye on the longview -- sacrificing a little short-term muckraking or outrage for longer term stability.
No, it's not going to be different this time. Historical precedent won't somehow be disproved this time. Tearing down the Obama presidency from the left won't help progressivism. It might help progressive blog traffic when a Republican Congress or president are elected. But it won't help move the nation to the left.
And, yes, we can hold our president accountable. But, again, with smart politics. Things like positive reinforcement, holding back and shaming the real enemy, and criticizing, when necessary, with modulated, reasonable dialogue (constantly shouting "sell out" only turns into one long, loud screechy noise).