you are too optimistic! not...
sensibly skeptical. brutally realistic.
There is no one, not one single republican, of presidential mettle with the possible exception of Rudy Giuliani, like it or not.
And Hillary's status as Victim of Bill and Strong Woman and veteran De Facto President will trump him easily in the public mind. The others, on either side, are just that: side shows. They are not capable of being the president of this country, imho, and it will be a time of trepidation if any of them by some unfortunate turn of events manages to get elected to the office.
I suppose one thing that could do it is apathy. Apathy somewhere could get one of these side show politicians in. That would be sad indeed, no matter what party he claimed to be affiliated with, because this country is too much to be handled by an amateur. He'll be eaten alive and run too high a risk of making really dumb decisions out of ignorance of the true political and leadership tradition of the US, and the discretion required to steer this ship in international waters that are filled with sharks and landmines.