Why isn't Gore running?

[gorkay]

1) He wouldn't be guaranteed victory if he ran, because no one is ever a guaranteed winner. His chances would be excellent, though.
2) I think that if he were running, he would have announced by now, or at least done some of the things potential candidates do when they're thinking about it. He hasn't done any of them, as far as I know, so I don't think he's running.
3) I think his ambition to be President has cooled. He's discovered that he can lead a contented and productive life without it, so he no longer feels as if he needs it.
4) His sense of fair play precludes him from making an eleventh-hour run and pulling the rug out from under candidates who have been working hard for the nomination for months and even years-- especially Hillary.

[gorkay]

If Gore decides to run now, then he will have to come up with an explanation to why he is doing this after repeated insisting that he is not running. It will be very hard to explain that without appearing opportunistic.

There have been many, many candidates in the past who have run after repeated insistences that they wouldn't, and it didn't keep them from getting nominated or elected. Eisenhower is one notable example.