Depends on who you ask. Obama voters will tell you it's illegal for a state to secede, and that the issue was settled at Appomatox Courthouse.

Others argue that the War Between the States only proved that the Federal Government can suppress secessionist movements by force of arms.

Here's what Thomas Jefferson had to say about it...

"Whether we remain in one confederacy, or form into Atlantic and Mississippi confederacies, I believe not very important to the happiness of either part. Those of the Western confederacy will be as much our children & descendants as those of the Eastern." He wrote that if those of the Mississippi valley should "see their interest in separation, why should we take side with our Atlantic rather than our Mississippi descendants? It is the elder and the younger son differing. God bless them both, & keep them in Union, if it be for their good, but separate them, if it be better."