If as you say, that Trump did not want to confront Russia in order to prevent nuclear war (I don't think that was his motivation, but let's roll with your argument for a sec) then Trump was an appeaser in the mold of Neville Chamberlain.

As for his actual motivations, I think it had a lot more to do with wanting to make money in Russia as well as his admiration of autocrats.

> People are usually pretty rational on close inspection.

Large groups of people can be agitated and manipulated into being very irrational. Plenty of examples from history.