It is not so much that America is ungovernable, as that Mr. Obama has done a lousy job of winning over Republicans and independents to the causes he favors. If, instead of handing over healthcare to his party's left wing, he had lived up to his promise to be a bipartisan president and courted conservatives by offering, say, reform of the tort system, he might have got healthcare through; by giving ground on nuclear power, he may now stand a chance of getting a climate bill.
Yglesias points out that Obama did, in fact, offer tort reform to conservatives, quoting Time's Karen Tumulty (5/5/09) on a meeting between Obama and congressional Republicans:
Obama said he was willing to curb malpractice awards, a move long sought by Republicans that is certain to bring strong opposition from the trial lawyers who fund the Democratic Party.
What, he wanted to know, did the Republicans have to offer in return?
Nothing, it turned out. Republicans were unprepared to make any concessions, if they had any to make.
More broadly, of course, Obama turned healthcare over not to his party's left wing but to his party's right wing, in the person of Max Baucus (the 10th most conservative Democratic senator, according to VoteView), who famously spent months unsuccessfully trying to craft a bipartisan compromise with Republican colleagues. Can you really follow U.S. politics at all and not be aware of this?
As for nuclear power, Obama made his call for a "new generation of safe, clean nuclear power plants" in his January 27 State of the Union speech, and in the month that's followed it has produced no Republican support for climate legislation–predictably enough.
How can people who get paid to pay attention to the Washington political scene get it so wrong? There is a bias built into the D.C. press corps that Democrats' problems are on the left and their solutions are to the right. As Extra! wrote back in 1992, looking back at the elections of '84 and '88: "When the 'pragmatists' lose badly with their centrist approach, they are repainted after the fact as radicals, so the strategy of tilting to the right can be tried again and again." That's what's was done with Bill Clinton after he ran into political trouble. And now it's happening to Obama.