No state may cede from the union. After the Civil War and Lincoln's Gettysburg Address, no one wanted to see something like that happening again.

"After the war, the Supreme Court endorsed Lincoln’s view on the constitutionality of secession. In 1868 Texas was a party to a case before the Court, Texas v. White, where the Court ruled that “when Texas became one of the United States, she entered into an indissoluble relation.” The Court put to rest any 10th amendment claims that states retain the right to leave the Union as they please, as Chief Justice Salmon Chase wrote that the Constitution, “in all its provisions, looks to an indestructible Union.”"(From: Could Texas Secede From The United States If It Wanted To)

So, no it would be un constitutional to cede from the union unlike what many say. We fight the Nazi left as a nation or divided, we shall indeed fall.