Maybe she is looking ahead to the 2012 presidential election. Good luck to her if so. She has vastly more experience of real life and of running things, making decisions and managing budgets that work than the present astonishingly inept incumbent.

Or maybe she has just had enough of the fountains of filth directed at her and her children. She deserves to be raped for not being a nice liberal lass, they deserve to be raped because they are her children, having a Down Syndrome baby instead of an abortion means she wants to breed a nation of retards, etc, etc, you get the idea. 

Left wing organisations respond to news of her resignation with (take a minute, guess…) attacks on her children.

These, of course, are from people who support the new, changed, more inclusive and compassionate leadership of the great BO.