Well, I have 3 theories: or I should say, I have read bloggers today who have put forth 11 or so theories and here are the 3 I find most plausible.

1.) One of those ethics probes in AK has borne fruit and a major scandal is about to break.

2.) Todd is involved in a scandal and she doesn't want the extra attention and publicity that will come with her still being in office.

3.) The "Vanity Fair" reporter is right, and she's suffering from a personality disorder.

In any case, I think she is finished politically. She's not presidential material (nor are most of us; that's not necessarily a criticism). I hope she enjoys the extra time with her family.

I don't think I'll bother to enrich her by reading her upcoming book, however.