Quote from Navin Johnson:
If the economy stays the same, I think it will be a very close race, but, Romney will win. Even in the RCP average of polls, Obama only gets 47.5% of the vote. If an incumbent cannot get 50%+ of the vote, then they are in trouble. 52.5% will vote for Romney, are undecided, or will vote for another candidate. 45% - 47% of the electorate will not vote for Obama. The electorate knows Obama. Most of the undecided voters will come to the conclusion that they do not want an Obama second term. Then, they will look at Romney. If they think he is up to the task, they will vote for him.
A political pundit (I can't remember who) told a good analogy. Imagine if you are married. Some one asks you if you would still remain married in 10 months. If your answer was undecided, then your marriage is in trouble.