From The Campaign Spot:

On the theory that the scrutiny of her children was the straw that broke the camel’s back, the consultant said, “From the interaction I’ve had with her, that would make some sense.” He noted that Palin had been “really down” at one point after the 2008 convention, largely from being separated from Todd and her children for days at a time; the campaign leadership was nudged to have the family traveling with her as much as possible, having a major impact on her morale. “They finally let her be a mom,” the consultant said.