I think it's not so much that Obama himself is a stealth Republican (though he is by consequences of his actions) as that he has a truly naive belief in politics as usual, in a democratic process by compromise. This is, after all, his greatest skill; if one takes nothing else into consideration, the passage of the health care bill would be an extraordinary achievement--but there is no democracy when perhaps fewer than 15% participate in the process, and an even smaller minority control those who do. This is not because so few vote, but because the majority don't have the money to buy those elected, or to pay their way into positions where they can become servants of the powerful few.
Obama's failure is that he doesn't seem to see this, or refuses to acknowledge it, or thinks that he can compromise the oligarchy into surrendering their winning hand--as though he were playing poker and after a player showed his 4 aces, he thought he could talk him into giving 3 of them to the other players at the table.
In this, the president he's coming more & more to resemble, isn't Lincoln, but Wilson: a brilliant, well-intentioned man utterly blinded by a conviction of his own good will.