The potential Democrats for 2016 are going to have amazing resumes.
Hillary Clinton was Senator for the third most populated state in the Union, and Secretary of State. And I'd say her political experience is equivalent to a senior adviser for Bill Clinton.
Hickenlooper and O'Malley have Executive experience as Governors and Mayors.
Emanuel has Executive experience as Mayor of Chicago, and Legislative experience in addition to White House work in two administrations.
Mario Cuomo is a New York Governor, who served as Attorney General in a large state (where he has some experience with Wall Street crooks) and in the US Cabinet as HHS Secretary.
Their best arguments would be that Obama was punished for Bush's economy, but that he also wasn't ready for the responsibility of the presidency, which explains some early mistakes that they can avoid.
The 2010 election meant that potential rising stars lost, taking the likes of Pennsylvania's Joe Sestak and Florida's Alex Sink out of consideration.
I could see an Al Franken suggesting that Obama's problem was that he just wasn't progressive enough.
The big question is what Obama would do. He would be in his Mid 50s, with high name recognition and the support of a few key constituencies, in addition to some attractive accomplishments. And he would have the excuse that no President could have been reelected with that economy.
Hillary or Obama would start out as the clear frontrunner.
In the unlikely event both choose to run, it would leave room for a third candidate who can argue it's time for someone new.
If Obama loses this year, there is no way he gets the nomination again. The Democratic elites hate him for the record losses he has caused the party at the local and Congressional level during his Presidency.