Obama's not only got the whole congress, if this one becomes a republican majority again, to fight against but also against the system (lobbies). i think people don't realize a president doesn´t have the whole power in his hand, hence why it is called a democracy.
All of you have to realize as long as interest groups or lobbies benefit from our current situation, changing policies it's gonna be extremely difficult for any president, whether democrat or republican. Presidency candidates will make whatever promises gets them the most votes, and once in office, they have to come to the aide of those who helped him get into office foremost.
Obama is a bright man with a whole lot of of good ideas, but you'll be a fool if you don't realize he's i nthe position he is in, by appealling to the needs of the elites which have put him in his current position.