From a theoretical and even philosophical standpoint, I agree with Andrei. If, say, a state were to successfully secede, then there would be no logical barrier for the individual to do the same. Unfortunately, this has not played out well historically. Even what is supposed to be the shining example of such an act, the original secession that would lead to what was supposed to be known as these united States (as opposed to The United States), was quickly tarnished by those who simply wanted to control the power and not remove it. I'd argue that this occurred well before Lincoln convinced enough dupes that "the Union" could not be destroyed, but that's matter for a different time.

The historical problems with secession are that even if one is managed successfully, it usually requires a lot of unnecessary bloodshed. When that occurs, resolve is often weakened. That tends to lead people into agreeing to accept whatever no "rule" is put in place, simply because they are too war weary and tired of what "used to be" to critically question what is now being erected in front of them. Kind of along the lines of "well ANYTHING has to be better than what we were just dealing with!"

Having said this, I am not necessarily opposed to secession as pathway to freedom. I just don't see how the odds are historically in favor of that being successful. I could be wrong, though. The goings on in Rojava for the past year or so are interesting, and worth keeping an eye on. Not exactly a secession, but working somewhat within that framework.