Behind in the polls and in key swing states, he throws everything he can at Obama.
By finishing out the primaries, Clinton keeps faith with her fans – and maybe helps retire her debt.
Clinton's positive rating has dropped, while Obama's image as a uniter has taken a hit.
His victories Tuesday make eight in a row and show he's eroding Clinton's core constituencies.
Florida's Jan. 29 race is the first with all GOP hopefuls contending in full.