> though then a deeper question might be, when is secession legitimate?
It's an entirely subjective question. Never, according to the state being seceded from or revolted against, and always, according to the secessionists and revolutionaries.
It's worth mentioning that the same American government that added the Second Amendment and spoke in florid prose about the blood-sacrifice of patriots and rebellion against governments also put down rebellions against itself.
>And is there any justification that the United States might simply accept secession of a state from the Union?
No. Cultural reasons aside, there is simply too much money and infrastructure at stake (to say nothing of political instability threatening its superpower status) for the US to be willing to lose even a single state.
It's an entirely subjective question. Never, according to the state being seceded from or revolted against, and always, according to the secessionists and revolutionaries.
It's worth mentioning that the same American government that added the Second Amendment and spoke in florid prose about the blood-sacrifice of patriots and rebellion against governments also put down rebellions against itself.
>And is there any justification that the United States might simply accept secession of a state from the Union?
No. Cultural reasons aside, there is simply too much money and infrastructure at stake (to say nothing of political instability threatening its superpower status) for the US to be willing to lose even a single state.