Anarchism

Kinda depends on the situation as always.

One aspect is obviously the civilians lives at hand. If we are speaking of a city, there's people to protect from the war. But then, what about the people living in the territories that are to be given back ? Are they at risk of a high persecution ? Then maybe it's worse a shot protecting them too. And even if not, will the states really hold back ? On a military basis at first, but also on an economic basis : won't they try to create a blocus to end the separatism ? How many time do you think it will hold as is ? Multiple years is already a quite longer time than most anarchists uprisings, so if that's somehow guaranteed, agreeing could be worth a shot.

Some deal would have to be done with some state at some point i guess, from a pragmatical point of view, every state won't fall at the same time. So if it appears you can't go further anyway, maybe it would be the right time.