By doing away with the concepts of right and wrong, Rawls has ensured that the de facto "right" is what most people in power think at any one time.  A government based on overlapping consensus operates within the Overton window -- the range of generally acceptable alternatives on any given issue.  The problem isn't just that alternatives outside the Overton window are automatically devalued; it's that for some issues the objective truth lies outside the Overton window.  Global warming is an excellent example.  Most reasonable people (by the Rawlsian definition) agree that the range of possible alternatives ranges from no action (the Bush administration's choice) to the 5-7% carbon emissions reductions proposed by the Kyoto Protocol (at least theoretically Obama's choice).  But the science clearly shows that only a 50% or greater reduction can stave off environmental holocaust.  In the Rawlsian bizarro-world, the science is wrong because it disagrees with the overlapping consensus.  Rawls gives us no way to move beyond the practical in order to achieve the necessary.

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Sadly, we live in that Rawlsian bizarro-world.  There have been plenty of presidents in our history who have elevated the overlapping consensus to a high art through the ideas of "bipartisanship" and "getting things done" -- think of Bill Clinton's "triangulation" or Eisenhower's inveterate moderacy.  But few (perhaps only John F. Kennedy) have venerated the overlapping consensus as itself the supreme good of the nation in the way Barack Obama does.  Few have failed to spend political capital on expansive policies, not because they feared losing reelection, but because they believed doing so would be breaking a sacred trust -- but Obama is one of those few.

Read his books and you'll see that, despite the fact that Obama holds strikingly liberal views on a variety of issues, his anger at the Bush administration is directed not at its policies, but at its politics.  For Obama, Bush's supreme betrayal was in breaking the Rawlsian consensus.  Bush's extreme partisanship, his utter disregard of the Democratic members of his government, turned Americans against each other and polarized the electorate.  For Obama, that was Bush's greatest crime -- because to the President, we are a nation of consensus before we are a nation of laws or dreams or anything else.

It's the only interpretation that explains Obama's baffling and infuriating rejection of progressives and his embrace of the moderate wing of the Republican party.