It doesn’t matter if he gets elected or not. Enough people support the kind of fascistic nationalism that he represents that we will have to deal with it eventually. History says that voting will not be sufficient. We should all prepare ourselves for that.
It should also be noted that this is not limited to America. Fascism is gaining ground all over the world, especially in the West. I believe that’s largely due to traditional politicians being unwilling or unable to address the concerns of their voters but ultimately the cause is largely irrelevant. We are all going to have to remember the lessons of history in one way or another.