Guns,
I think it's a mark of Hillary maturing as a political figure. She's figured out that she can only go so far when allied with the reactionary against-everything crowd. It's nice to have someone to vote for who stands FOR something instead of merely being AGAINST what their opponent says. I think that's why Bush won both elections... He came across as being FOR stuff instead of just being against whatever it was the other guy said.
Of course, any President who actually ACTS on their principles is going to get ripped a new one, but that's the nature of the job. Even if 75% of the country likes your ideas, chances are less than half will agree with any actual implementation of those ideas, and that means that you'll end up with less than 40% who agree with you. That's why Clinton's numbers went up after he dropped the gays/military and national health care system - people loved the man as long as ne never actually acted on any of his ideas.
Bush and Cheney act. People hate that, and now the polls reflect both the people who don't like their ideas plus the people who don't like the implementation of ideas they do like. Ah well.