I know what the term means. In the movie, the husband is INTENTIONALLY messing with the lights (and other things) with INTENT to drive his wife to the point of insanity.
The key here is the word “intent”.
Someone who makes up “alternative facts” because they don’t like the real facts — and who randomly makes up conflicting alternative facts — but who does so without the INTENT to drive people crazy — isn’t (IMHO) remotely like a true “gaslighter”.
The end result of what Trump does to the American public may be very similar to the fate of the poor woman in the movie…but I don’t believe he’s doing it intentionally. I don’t think he’s that clever.
Narcissistic Personality Disorder explains everything we know about the man — and NPD is all about “self”. A typical NPD sufferer doesn’t care enough about other people to construct elaborate plots to confuse them.