I think you defeated your entire argument with these two sentences. Our law frameworks have deveiated so far from the constitution on guns, privacy, free speech, religion, etc that we no longer continue to be a nation ruled by the Constitution. 20,000 new laws per year, most of which are based on previous laws which alrady defy the constitution.
Also, no one said the break up of the US would be legal. Thats totally irrelevant.
A break up would be better for the people who live inside the borders glaimed by the US government.