The Democrats have a substantial Electoral College advantage going in. Clinton's advantages are highly likely to result in her election, if the following things hold:
- Hispanics and African-Americans enthusiastically support her, thus angrily overcoming what they see as Republican efforts at voter suppression
- Clinton is a calm, cool, domestic and foreign policy expert in debates; and steely in calling Trump out on selected outrages
- Most of Bernie's voters see her as vastly preferable, even if coming to this view requires nose-holding
- The Democratic ground game is as dependable as in the last 2 Presidential elections
- Reputable Republican leaders and columnists, including especially Republican foreign policy establishment, counsel voting for Clinton (with pointed detail, and while encouraging support for Republican candidates down ballot)
- Nominee Trump continues to say outrageous/wacky things, raising further questions among independents and suburban Republican women about his stability, his lack of qualifications
Now, Trump may well make all common electoral assumptions irrelevant. He may be immune to all historical precedent. But that's the only way he will win. Maybe that's exactly what will happen, and he will bring in so many new voters and thus put into play several Rust Belt states. Not impossible, just unlikely.
So the logical question is, how can she possibly lose? She can, but the odds of winning are in her favor.
I think Kasich, Cruz, and some of the other 2016 Republican candidates assume it's likely Trump loses, and so will already have easily convinced themselves that their party will come to its senses and nominate one of them in 2020 (Kasich, Cruz, Rubio, Walker, Fiorina, others). Kasich is probably calculating just now on how long he can effectively continue his case for 2020.
Governor Rick Scott or Governor Chris Christie.