Michael Bloomberg could be just one of the people making 2012 crowded and enabling the eventual winner to get by without that whole mandate thing.
With a grain of salt about predicting the future, a word from Hedge World:
Usually an incumbent President can be sure of re-nomination as the Democratic candidate, but Obama’s popularity is so low and his effectiveness as President has been so wanting that a challenge from Hillary Clinton is a distinct possibility. Clinton has the Prophet persona and would command the respect of Americans looking for foreign relations expertise. A failed challenge to Obama’s nomination would likely weaken Obama and allow the Republican candidate an easy victory. A potential wildcard would be an insurgent independent campaign by billionaire Michael Bloomberg. His financial background and moderate positions on social issues could attract moderate Republican and Democratic voters. Another possibility is that the Tea Party is unable to assimilate within the Republican Party and decides to nominate its own candidate. This could lead to an 1860 like situation, with four candidates vying for the Presidency. The victor in this scenario might need to be selected by the Electoral College. The next President could be elected with less than 40% of the popular vote.