His scandal kind of ruins his campaign, but if he won Iowa, Hillary would win subsequent states, making Obama and Edwards drop out. She would win the nomination. In the election, she would win by a decent margin. I think she could've won Montana and North Carolina but lose Indiana, I don't really know.
I'd like to think that she would've appointed Obama to SoS and he would be the one running in 2016, and Trump wouldn't run because he supported Hillary in '08. The map might've looked like this:
Secretary of State Barack Obama/Senator Tim Kaine - 273 Electoral Votes
Senator Ted Cruz/Busineusswoman Carly Fiorina - 247 Electoral Votes
Tossup - 18 Electoral Votes