What if they moved to Japan because of an opportunity provided by a Japanese organisation that needed their skills, and then they spent enough time there that they had buy in to the community and were a recognised member in it and were valued by that community?

I don't think this is too hard to imagine applying to a person living long term in Japan and definitely not hard to imagine in the US, where there are no true "Americans" in the first place, apart from maybe the indigenous peoples.

If I lived there a long time, I still wouldn't be Japanese. Look, it's definitely an emotionally charged issue the longer someone has been in a place, but that doesn't change the basic facts. We can discuss the merits all day long but not the legitimacy of the government to decide who can and cannot stay.

For the purposes of this debate, "Americans" means citizens and those that can vote, the ones to whom the government answers.

> We can discuss the merits all day long but not the legitimacy of the government to decide who can and cannot stay.

Why can't we discuss the legitimacy of the government?

Geopolitics is inevitable: everything's interlinked--trade, laws, defense, research--everything. If a nation wants to persist and prosper, it needs to play the game; being an aloof loner or a blatant bully won't get you far.

It wont get you very far seems to ignore centuries of aloofness and often very bad behavior being rewarded with great success.

Conquest fell out of fashion with the bomb; it's all proxy wars, psyops, and deniable covert/cyber attacks now. Slamming the door on H-1B’s (while it might be nice for my own income) weakens American companies and sends world talent elsewhere, like China. Who's only too happy to fund infrastructure in Greenland/Africa/Europe to extend soft power across the globe while siezing harder power closer to home (Hong Kong, South Sea expansionism, etc). Sitting out the game isn't an option, and going at it alone ain't much better.

Are you linking to "a politically organized body of people under a single government" or "a race of people, large group of people with common ancestry and language"?