You could have residency requirements, not citizenship requirements. Maybe not doable in the US, but perfectly possible in countries where people are required t

You could have residency requirements, not citizenship requirements. Maybe not doable in the US, but perfectly possible in countries where people are required to officially register the main place they live at, e.g. in Germany. That would make more sense, anyway. Citizenship is just a weird concept, as is much to do with nations and nationalism. Heck, throw in a five year delay (or whatever the voting period is) and you may even be able to placate the eternally xenophobic weird people (nah, not gonna happen …).