[Conservative Actuary]

I think their are two main reasons.

1) He will be smeared by the main stream media to a level that has never been seen before. No matter how strong a person you are that is hard to stand up to or put your family and friends through.

2) Money. Big business wants amnesty and they will keep him from raising the money necessary to run.

[cripplecreek]

Let's not forget that he never made any committment one way or the other and has often said that he doesn't really want the job.