Spitzer got caught by laws that he had had passed.
He was clearly, at that point, being self-destructive, probably having lost the will to govern. If it wasn't that scandal, it would have been something else.
What you need is for him not to have given up/had a mid-life crisis/whatever it was that happened.
But, yes, if he had managed to keep his self-discipline and keep focussed, he could have easily ended up as a presidential candidate.