Clinton's positive rating has dropped, while Obama's image as a uniter has taken a hit.
New York governor met little sympathy or support over sex scandal.
Calls for his resignation mount, after the ethics crusader said he failed to live up to his own standards.
Many see it as folly for him to enter the presidential race one more time.
His victories Tuesday make eight in a row and show he's eroding Clinton's core constituencies.
The house that Reagan built shows cracks, as the far right chafes at McCain as GOP standard-bearer.
The state's economic woes are the central focus for Romney, McCain, and Huckabee before Tuesday's primary.
On the Democratic side, a potentially historic clash lies ahead. For the GOP, Michigan is the next test.