Rather than one big democracy, you have dozens. New York, California and Texas get to do whatever they want but they don't get to tell each other how to live. Then people like me can move somewhere with low taxes that leaves you alone and those who want it can move Uncle Sam into their guest bedroom. We will all get together if someone invades. Like a weaker EU.
Technically sure, but in practice states have little difference between them. Any issue of consequence is federalized, can't have a low tax state with federal taxes being so high for example.
Those states have a hell of a lot more variance in their government systems than other modern republics, e.g. in Western Europe. I think your calibration is way off on this topic.
Do you see a problem coming up here? "Why should we protect X if they don't do things the way we do?" (This sentiment already exists in the US today, it would just get more common)
Beacuse they would do the same. We currently have mutual defence pacts with nations that do a lot worse than any of your neighbors would do. Don't have to like someone to engage in a mutual defense.
id love to peek into the alternate timeline where America still won the revolutionary war, but stayed not united. what kind of empires and alliances would have formed? what wars would have been fought? would technological advancements have stayed regional or even come to fruition at all? what would the borders in the Americas even look like?
https://plato.stanford.edu/entries/republicanism/
Rather than one big democracy, you have dozens. New York, California and Texas get to do whatever they want but they don't get to tell each other how to live. Then people like me can move somewhere with low taxes that leaves you alone and those who want it can move Uncle Sam into their guest bedroom. We will all get together if someone invades. Like a weaker EU.