That the US would go to war over the hacking of a non-governmental institution is ridiculous, and whoever is spouting stuff like that should immediately lose quite a bit of credibility with whoever is listening. Only congress can officially start a war, and if the president started getting aggressive with a country such as powerful as Russa over something so small, well, there would be some interesting ramifications to presidential power. Remember, congress has the ability to amend the constitution.
If a sufficient electoral base exists to elect Trump, a sufficient electoral base exists to get him sufficient legislative support (sooner than new people are elected, perhaps, simply by raising the prospect of electoral danger to present incumbents) to implement his policies.
Edit: Also, to be clear, if he does have legislative support because enough people support him to elect representatives with similar agendas, that's not really something for me to be worried about, as that would be no different than any other candidate. If it's the will of the people, so be it (as much as I dislike it).
The interest groups that care generally want the status quo preserved.
If Trump is not destined to do this, then I think there is little danger he'll be elected.
Note, the same applies to HRC.