Simple. Trump says he was against the war.
THERE. Right from the horses mouth (and MIND)
Only Trump knows his own mind. If he says he was against the war, then he was against the war.
If he said otherwise in order to support the president or support our troops during wartime, that is totally understandable and not inconsistent with being against the war. In fact it would be admirable. (Ted Cruz take note)
“Just ‘cause I said it, don’t mean that I meant it,
Just ‘cause you heard it”
(Adele)