Compare this to Bush/Chaney who had very small margins in Congress, yet got everything passed. Several Republican congressmen lost their seats over the Iraq war - but they stayed with Bush until the end. The discipline and obedience of the Republican party is unmatched. They are much better with strict hierarchies. Obama, on the other hand, could not get Blue Dog democrats to support his agenda. The Left allows too much freedom and dissent in the ranks. They are like the irresponsible parent who allows the spoiled child to talk back. Dick Chaney, on the other hand, does not take shit. If a republican breaks ranks and votes with the democrats, he loses his job. If a democrats breaks ranks, he ends up like Joe Lieberman - in charge of a committee.
This obedience disparity partly stems from the institutional structure of the Republican party. Grover Norquist - backed by insanely deep pockets - is able to force all congressmen to sign a pledge. If they don't sign the pledge, they don't keep their seats. Indeed, business supplies massive funds to primary any congressman who does not play ball. Whereas the Left lacks a well-funded operation to impose its agenda on its party apparatchiks. Why? Because business is not going to fund a party that wants to raise their taxes and tighten regulations (even though they have to fund the dems pretty heavily as a hedge, especially in non-republican electoral cycles like '92 and '08).
Republican agendas have a vast network of think tanks and well funded groups who keep their issues alive when they are not in control of Washington. People can spend their entire life inside movement conservatism, producing data and talking points to feed thousands of media sources. The movement rewards obedient members with well paid careers; they punish dissent through exile. The anti-tax movement does not die when the Republicans lose the presidency. Whereas nobody worked on universal health care after Clinton botched it in '94. When Obama picked it up again in 2008, he defaulted to Bob Dole's & Mitt Romney's plan. If the Liberals had any power at all, they would have had a well-developed, well-funded battle plan. Instead, they stumbled through health care with no clear vision or leadership. (Does anyone know how long the neocons through PNAC were preparing for Iraq? They had intelligence agencies, media, and congress perfectly orchestrated. The Left, on the other hand, is a flaccid mess. They gave up on politics after LBJ > Vietnam. Granted, SDS blew up a few monuments, but they retired to cushy university jobs)
The Left needs another LBJ - someone to play Texas hardball with anybody who does not obey the leader. Obama is not that person.