Unless someone has access to the TARDIS, the past cannot be changed. Our knowledge of history can be changed, and there are some people who can influence our perceptions of what happened by putting their own spin on it.

While Trump is in power he can influence our perceptions of history but as soon as he loses that power there are other powers who can change the perceptions of *his* history - or he succumbs to his medical conditions and falls off his perch.

Watching clips of his speech to the UN this week, I think he has managed to change his own history in the eyes of the world and its leaders, and not in a good way.