Obama is the indirect cause but his bringing to light the laundry and tactics of Israel is what's causing the americans to shift. Too often it's all been hush hush and US media outlets and politicians never would say or do anything against Israel for fear of the backlash...just ask Bush senior. If Bibi gambles on a 1 term Obama presidency, Bibi and Israel will lose dearly with a 2nd term and pissed off Obama. Good luck with that mentality.
Motorcyclist in his 20s dies after crashing near Gedera (Haaretz)
from the article: Envoy to U.S. Michael Oren denies saying Israel, U.S. drifting apart