> In the multilateral case, recognition of Taiwan by the UN has long been something that China has had veto power over.
I think you are just stating that that is part of the international law, right? Law is just law. It went to effect for stakeholders agree that they can abide by bits ruling.
Texas is not independent because US does not allow that. Right? Because the law dictates that the sovereign power is legally the care giver of a group of population on a land.
You are mixing law and self conscience.
https://www.lowyinstitute.org/the-interpreter/would-war-over....
This is relatively balanced description on the issue. One can certainly see that the politics have made the matter intentionally vague.
And nternational law is not necessarily written. It could be some commonly agreed principles. For example, there is no written law says US government can govern the land on here. It's based a certain aggreed upon concepts in people's mind.