Rush is right. She would not burden Bristol with the guilt. Sarah-Cuda, indeed!
I see it like this. Palin told McCain about Bristol’s pregnancy but said that she is so young and being picked like this for the Veep slot was so sudden that announcing the pregnancy on the first introduction to America might be too much for the girl.
It was only two days later that the liberal blogosphere went nuts over thinking Trig was secretly Bristol’s child, and that the Governor had faked her own pregnancy.
So they were forced to announce Bristol’s current pregnancy in order to dispel those other rumors. Poor Bristol did not get even a week of peace before her pregnancy had to be announced to the entire world.