1) It s the economy stupid Romney campaigned on the economy, but turns out the economy wasn't as bad as Romney could hope. Job numbers turned out to rise and to make matters worse: Republicans had nothing to do with it as they have been blocking everything on the federal level
2) Monay talks Money spending on the campaign adds and the stricter regulations for GOP candidates (their campaign money goes largely to the party)
3) "the Unkown issue":Sandy showed that Obama can handle crisis moments very well, governor Christie helped a lot by saying "thank you" as it showed for independants that he can work on a bipartisan base. It s odd to say for me (being not so religious), but Sandy was like "a gift from god" for Obama's campaign
4) Republican primairies was no cakewalk for Romney, he got his image fairly weakened while Obama stayed out of the mudthrowing and kept his image clean. It exposed several weak spots of ROmney: flip flopping, being a mormon, having money in swiss bank accounts to avoid paying the taxes he should if he had it in the US
5) Bin Laden dead is Obama his accomplishment
6) Romney had to move too far from the right to the center, this made him lose a lot of credibility on both sides ( with both conervatives and independents).
7) Republicans lost the latino vote (they still had it under the previous republican president Bush), US demographics are changing, you can not survive politically on white votes alone anymore