Thus far there are five major competing theories as to why Caroline Kennedy pulled out of the Senate race so suddenly and mysteriously. We list them, and give exact statistical odds, below:

[Odds: The probability that this was the primary reason she pulled out.]

Here's what you've missed if you've had better things to do for the last 24 hours than keep up with the by-the-minute changes in the Caroline Kennedy story. We know she isn't going to be the next junior Senator from New York. We have no idea, however, why not. She announced last night that she didn't want the seat anyway, but in such an incompetent manner that all anyone in political circles has been doing today is collecting the various theories of why she dropped out. These are the five being most discussed.

1. She was incompetent, and pulled out to avoid the embarrassment of not being picked: This is really the most likely scenario. Her push to start at the top was a bad idea from the beginning. She didn't embody the HOPE of the Obama era. At least all her connections and money landed her some political consultants who were smart enough to tell her to get out while she was—if not ahead—at least not totally destroyed.
Odds: Even

2. She had tax and nanny issues: Well, sure, it's quite likely, if you believe the up-to-the-minute prevarications, that she did have issues with taxes and/ or an illegal nanny. So that stands in favor of this explanation. But calling this the primary reason she dropped out presupposes that had she not had these issues, she would have been the pick. And we still want to give Gov. Paterson more credit than than.
Odds: 2-1

3. Her marriage is a sham: One of the unfortunate things about going into politics is everybody wants to pry into your sex life. That's stupid America! So the Enquirer was floating the idea that CK's marriage to Ed Schlossberg was a big fake, and that they've been amiably separated for a while, and who knows what various tabloid-worthy stories might lie behind that? Just scandalous enough to kill her bid? In a state that still loves Giuliani, it's doubtful, but you never know.
Odds: 5-1

4. She had an affair with Arthur Sulzberger, Jr.:The supposed love interest between CK and the NYT publisher remains totally unverified dinner party gossip material. But the Times' close—too close—coverage of CK's campaign didn't do anything to help kill the rumor. At most, this probably added up to one more thing on the negative side of the scale for Kennedy, rather than being the main thing that did her in.
Odds: 8-1

5. She was worried about her sick uncle Teddy: Since Uncle Teddy's own people were pissed when she floated this explanation, and because he was just as sick when she started her bid for the Senate, nah.
Odds: 25-1