The legal case for the legitimacy of secession is sound today and has been since the Constitution of 1787 (despite Lincoln's treasonable violation of it). The founding states voluntarily joined the Union and could voluntarily leave it. Nowhere in the Constitution is the right to secede denied. See Alan Buchanan's Secession (1991); also Joseph Sobran's articles "The Case for the Confederacy" and "Honest Abe" in the Conservative Chronicle (Aug. 25 & Sept. 1, 1999).