I guess it depends what meaning of "liberal" you go by. In the US he would not be a liberal at all (in the sense of a Hubert Humphrey).

He was consistent career-long in hating a few things as far as I can tell : prudery, collectivism, and slavery (although he'd say the last two are redundant).

"Cold warrior libertarian with a frontier fantasy" is I think how I'd try to say it for an American audience.