we'll always have people like donnie who, for various reasons, should never be allowed to wield anything like the power of the oval office.
such people will always exist, and some chunk of them will attempt to gain such power.
no stopping that.
what we can do something about, and can realistically wish for and work for better, is to change the people and the institutions that enabled and continue to enable him.
personally, i believe it's the media that's in most need of changing, though another possibility is the electoral process. donnie got a lot of votes from republicans who would have preferred some other republican but ended up not having that choice. there are other voting methods, where, e.g., where instead of having a single vote, you rank order all the candidates.
no voting method is going to be perfect, but we can certainly improve on what we've got.
that said, the media is still the #1 problem, imho. they gave donnie 80% of the coverage, drilling into our heads that at least he's someone we ought to be eager to hear speak, then using the rest of the time to say hillary's mired in scandal -- all without really saying how horrible a president donnie would be or how ludicrously made-up hillary's "scandals" actually were -- is inexcusable and a huge reason (yes, there were others) we ended up with this nightmare.