Not an explanation
A few stubborn defenders of Trump believe that he honestly changed his mind about intervention after seeing "evidence".
Mind-changing doesn't work that way. Best and most relevant example is Mussolini, who
began in politics as a pacifist opposing Italian empire in 1911, then by 1914 carefully favored getting into WW1. By the time he achieved full power he was a full-fledged imperialist. (This story was nicely dramatized by
Strange as it Seems.)
I can see the same three-year transition in my own views. In 1989 I was non-interventionist, then by 1992 fully neocon. In 2007 I saw where neoconism was leading, and by 2010 was back to solid non-interventionist. Each** transition took about three years from first doubt to final flip.
Trump's "change of mind" took EXACTLY ONE DAY. There are two possible conclusions: Either he's totally senile and random, or he was faking the non-interventionist view. Change of attitude is NOT a possible explanation.
= = = = =
** Footnote: The neocon period corresponds exactly to my TV-watching period. I didn't own a TV during the '70s and 80s. Bought a TV in 1990. Unplugged it in 2010. The causation wasn't quite direct or simple, but the correlation is clear. TV locks you into globalism. If you want to see beyond globalism, you have to remove the TV.