Yeah, there's at least a supreme court precedent, set by Texas v. White. It outlawed unilateral succession, but ruled that "revolution or consent of the states" can lead to secession.
The whole point of secession, whether in the US, or Catalonia, or in China[1], is that you have reached a point where you are not able to come to a bilateral compromise on issues that affect you.
If you need bilateral support to exercise your right to self-determination, you don't actually, in practice, have any right to self-determination.
It's like saying that you have the freedom to leave your abusive job, but only as long as your boss lets you quit. That's not freedom, that's slavery.
[1] And yes, I am aware that the case in Scotland was a bit different. Props to the UK for being, as an outside observer, reasonable about the whole affair.
If you need bilateral support to exercise your right to self-determination, you don't actually, in practice, have any right to self-determination.
It's like saying that you have the freedom to leave your abusive job, but only as long as your boss lets you quit. That's not freedom, that's slavery.
[1] And yes, I am aware that the case in Scotland was a bit different. Props to the UK for being, as an outside observer, reasonable about the whole affair.