It’s something I’ve contemplated even without worrying about whatever people seem to think about the current political situation. The terms in the OP – assuming I have some mechanism to be let in – significantly broadens the choices I have available in this hypothetical.
My traditional answer is Mexico, because I’ve lived there and it mostly doesn’t suck if you’re not in narco territory. I love the people, food, attitudes, traditions, beaches, culture, and most everything about the country and its people. Obviously this isn’t a political decision, because Mexico’s government is inarguably worse than anything that can possibly happen in the United States.
But given the lessing of contraints by the OP, then the next obvious answer is Canada, particularly Ontario, because the culture is nearly indistinguishable from the Michigan culture. I said nearly; don’t get pedantic. I’d miss a bunch of our freedoms, but not really, because it would be pretty easy to come back to Michigan to enjoy them. Oh, yeah, proximity to Michigan is a big plus here.
France comes to mind, particularly smaller cities such as Tours or similar, or even smaller. Culturally we Americans are stupid and make too much superficial fun of the French, because they’re really our brothers in spirit, culture, and attitudes. Yeah, yeah, Paris has a bunch of folks with bad attitudes, but so does our own New York City, but it also has a lot of great, patient, wonderful folks. But also I wouldn’t want to be in Paris anyway, and the rest of the country is not Paris.
Funnily, I used to live in Germany, and I love the Germans, and my step-mother is German, but I think I’d not choose to live in Germany given the other options. The abovementioned French are much more culturally compatible with us. No, I’m not being ironic.
New Zealand. Oh God, I love nature, and the pure variety that’s within a reasonable distance is unique in the world. Maybe not unique in the world, but unique in my experience. Driving from the east coast to the west coast is almost a mirror image of the same trip in the USA, but in a day’s time instead of a week’s. English language, pioneer spirit, and culture are all great. I’d miss some of the freedoms, and it’s almost an antipode of home, so the distance would suck unless I were totally and completely all-in, though.
South Africa was on my list for a while. It’s been a long time since I’ve been there and so I’m not sure how the race/political situation affects things today. Nature is a big draw, but I really loved the mix of cultures – Afrikaners, English, and 10 different types of blacks – made things a really cool mixing pot, and it was incredibly easy to be friends with any of them. In parts I spent most of my time, though, crime – in particular violent crime due to continuing racial inequality – was a major security issue. I’d have to spend a lot of time here again before making a decision.
I lived five years in China and my wife is Chinese and my two children are half Chinese. Nope. Don’t want to settle there. It’s the very epitome of fascism. I’d be happy to take another international assignment there, but no way in hell would I ever consider it as a future, permanent home.