Facepalm

Start by asking them to define their terms. "Belongs", "imperialism", and "fascism" are the ones I'd like to see definitions for. Though I've gotta admit that I'm not very clear on "fascism" these days, which seems to be a term with many meanings, depending on who is using it.

If someone's argument depends on a lack of logic, getting them to elaborate on it can make that obvious.

They'll probably avoid the question though because they aren't there in good faith.