> It's surprising the extent to which legal scholars assume that state exits from the Union are a settled question. Ultimately, it's unlikely that the federal government would or even could force a state into compliance once the state government and courts have opted to treat state law as taking precedence above federal law.

That's an interesting Taiwan-ish model for succession. It probably has a better chance of success than the kind of outright succession the Confederacy tried, because it could be conducted slowly while still paying lip service to the Union. At each small step, military intervention might seem like too extreme of an escalation.

Though it still would be difficult. At some point it would require the state citizens to start breaking federal laws in very obvious ways (e.g. stop paying federal taxes), but I doubt they'd be fine with not crossing state lines in that case. Also a lot of the money in state budgets pass through the federal government, so it would probably be really expensive to replace that without some of the more extreme steps.