I have talked about Trump to one. He disliked him on the surface level because his personality seems absurdly rude by Japanese standards, and because he was worried about how Trump's policies would affect the Japanese economy. Mind you, this was a right leaning 2ch poster, not a lefty or a riajuu. However, once I told him about Trump's actual positions, and asked him to imagine situations like Japan being flooded with illegal immigrants, his opinion seemed to improve. He told me that he hadn't really thought about Trump from an American's perspective before, and I think he realized that Trump's positions are really not that different from those of a typical Japanese politician.
He's told me, and I've observed a little myself, that most Japanese people, even the younger generations, lean right. They don't want immigration, they care more about pragmatic economic policy than anything, they don't need to rally about expanding social services because their existing ones work well already, and basically they think the ruling right wing party is doing a good enough job and don't feel the need to rock the boat. They have their own crazy lefties feminists etc. but nobody likes them.
There is a challenge in that the far right wing of Japan, which has been active for much longer than we have, is sentimentally rooted in anti-Americanism and foreigners in general. They hate being occupied by the American military and having foreign governments try to impose their culture on them. They want the white piggu to go home and rebuild their military. They get angry at their government for bowing down to foreign pressure to censor lewds, and these sentiments are only going to get stronger with the upcoming Olympics. I really understand their points and think we could see eye to eye if we could just talk about it, but not only is there a language barrier, but I also get the impression that the Japanese far right genuinely dislikes foreigners and wouldn't want to talk to us in the first place. So ironically I think we would have an easier time swinging average Japanese people to our side than whatever their equivalent of /pol/ is.