I think that the answer may be a lot simpler than any of the scenarios mentioned below, even though there may be some truth there. When president accedes to office he has a certain amount of "political capital" and he seeks to use it as efficiently and effectively as possible, as well as quickly since political capital evaporates as pressure and temperature rise.
President Obama decided to undertake healthcare reform as his landmark and legacy program immediately, in addition to and in spite of the dire economic situation that he inherited. Being the political being he is, he held his nose and made the deals necessary to get the required votes. It also seems that the president underestimated the intensity of opposition to him and the level of obstruction that the opposition would rise to.
President Obama also failed to grasp the nature and extent of the economic debacle that was unfolding and assumed that his people knew how to handle it. Moreover, he was heavily influenced by interest politics and not only didn't receive the best economic advice but also ignored the best of it if it was even presented to him.
Given the cards he was dealt, he has not played his cards all that badly, except economically. Bu it can be argued that he got "bad advice," as Bill Clinton complain about his advisers. Neither had the economic chops to be able to distinguish between actual experts and the highly credentialed and successful. I don't know that either can be faulted greatly for that shortcoming. They picked "the obvious people." Even FDR got lucky in picking Marriner Eccles, comparing him against many of his other picks that were much less successful.
Be that as it may, passage of the Affordable Care Act was a signal achievement, even with all its warts, as well as fits and starts on launching. The AFA has permanently altered the political landscape, and still would even if it were repealed, which is unlikely at this point. It's a very big deal in that it advances universally available publicly provided healthcare as a fundamental human and civil right.
The president also turned out to be more pragmatic than principled in just about every other area as well. He is a centrist that strongly believes in bipartisanism even when the other side is not only not willing to negotiate but declares the intention to break his presidency.
I think that historians will come see President Obama as much more skillful politician that we give him credit for now. He is less of statesman than most people had hoped for, but he had to contend with an obstructive opposition, an oppositional military, and a bureaucracy that had been stacked against him.
So while many are disappointed at the president's priorities and choices, they were his call based on information that is not available to the public and speculating about in the dark doesn't advance the game. The way to advance the game is by turning up pressure, and there is still time to do that. The president is feeling the pressure from minorities about immigration and he has promised to act on it, for instance.
However, there are also stains that will darken his legacy, too. Again, but his choice, and therefore his responsbility. A person of greater character would have risen above politics and adhered to principle and decency, not to mention the constitution and the laws of land he took an oath to uphold. Some would even argue that this, and the potential consequences for the country and world, overshadow any good that he might have done.
Consortium News