Not legal? Rather a bold statement, I would say. Last time anyone attempted formal withdrawal from the United States, something like 125 years ago, the armaments of the United States blocked the path to independence. The Union endured. But that settled only the practical, not the theoretical, side of the question.
Enough said anyway about the Late Unpleasantness of 1861-65. What about the secession movement -- if you care to call it a movement -- suddenly drawing so many gasps of horror and indignation, so many hoots at the screwballs whooping it up for flat out withdrawal from the Union, any state that might want to? More than 700,000 signatures on various secession petitions around the nation! Northwards of 100,000 in Texas alone! It's hard not to notice.
Enlightened opinion on secession is hostile -- as you'd certainly expect. Even a conservative Republican like Louisiana Gov. Bobby Jindal calls the clamor "silly." Behind the web posts and the signing of petitions lies, nevertheless, unarticulated dissatisfaction of the sort that sensible societies ignore at their peril. Timothy Stanley, a modern American history specialist at Oxford University, credits secession talk with "the feeling of a growing number of conservatives who feel emasculated" in the realm of 21st century politics.
This whole business is not my pot of tea, I confess. On the other hand, the would-be secessionists have hold of a principle too much ignored or irritably brushed aside in present-day politics and culture. It is a principle many others would benefit from examining boldly, never mind what the holy hecklers of the media might say.
The principle is that the United States of America took the shape of a plant, nurtured from the ground up, rather than that of a railroad spike, hammered in from the top. First there were states; the country followed. The Philadelphia founders, in 1787, represented states that were trying to strengthen their relationship for the benefit of all. For the Constitution to come into effect, each state had to ratify it. The nature of the constitutional compact made Southerners believe they could abandon it at will.
Who ever heard of a compact you couldn't quit? Who ever it was, the military power of the North made clear that was how things were going to be. No state was going anywhere, then or later.