It's Already Been Settled

Is the US Declaration of Independence illegal?

In Philadelphia, American and British lawyers have debated the legality of America's founding documents.

What's to debate? There was a fundamental disagreement, the war settled it. The U.K. has no further say in the matter. They bring up the Civil War in the article. Same thing, the war settled it, even if it had gone the other way.

It is important to settle differences peacefully and within the law - 100% of the time would be ideal, but there are times when it is just not possible. It might be argued that the people of North Korea are obeying the law of their land but wouldn't it be far better for them if they fought a revolution against 'Dear Leader' and freed themselves from his tyranny? It wouldn't exactly be legal by North Korean standards would it, but who cares?