Of course this is messy throughout history and in many cases today, depending on how far back you want to go with old claims and, even more explosively, new claims.
Where are you on Kosovo? Taiwan? How much do you base your perspective on values of liberty and rights? Desires of the populations involved? How small in scale and integrated in territory do you want to go? How great a majority need be involved? How much do you fall back on realpolitik? Possession being 9/10s of international law?
At one time I had familiarized myself with Kosovo, but I have forgotten most of it. What I recall is we were probably on the wrong side of that conflict.
Taiwan is the rightful government of China, so far as I'm concerned, but at the very least they should be supported in maintaining their independence from the People's Republic.
How much do you base your perspective on values of liberty and rights?
My entire argument is that people have a right to independence based on the Natural Law premises of this nation's own founding.
How small in scale and integrated in territory do you want to go?
Till this notion is better explored, I simply default to Lincoln's stated position on the subject.
"Any people anywhere, being inclined and having the power, have the right to rise up and shake off the existing government and form a new one that suits them better. This is a most valuable-a most sacred right-a right, which we hope and believe, is to liberate the world. Nor is this right confined to cases in which the whole people of an existing government, may choose to exercise it. Any portion of such a people that can, may revolutionize, and make their own, of so much of their territory as they inhabit."
I would also point out that the Declaration of Independence applied to states and it was some of these very same states that declared independence in 1776.
Are we to believe they were justified in declaring independence in 1776, but "four score and seven years..." later they are not?
How great a majority need be involved?
Well clearly a greater number would be better, but most of what we do as a nation involves a majority greater than 50%.
How much do you fall back on realpolitik? Possession being 9/10s of international law?
Philosophy and reality do not always conform to one another. I would favor the fundamental principles involved, but the guy with the guns often makes the rules and cares not about principles.