Sorry, teabaggers (and Governor Perry), but even Justice Scalia says you're wrong.
To begin with, the answer is clear. If there was any constitutional issue resolved by the Civil War, it is that there is no right to secede. (Hence, in the Pledge of Allegiance, "one Nation, indivisible.") Secondly, I find it difficult to envision who the parties to this lawsuit might be. Is the State suing the United States for a declaratory judgment? But the United States cannot be sued without its consent, and it has not consented to this sort of suit.
This letter from Justice Scalia was in response to a screenwriter who wrote to all nine members of the Supreme Court, and retired Justice Sandra Day O'Connor, seeking their expertise:
I'm a screenwriter in New York City, and am writing to see if you might be willing to assist me in a project that involves a unique constitutional issue.
My latest screenplay is a comedy about Maine seceding from the United States and joining Canada. There are parts of the story that deal with the legality of such an event and, of course, a big showdown in the Supreme Court is part of the story.
At the moment my story is a 12 page treatment. As an architect turned screenwriter, it is fair to say that I come up a bit short in the art of Supreme Court advocacy. If you could spare a few moments on a serious subject that is treated in a comedic way, I would greatly appreciate your thoughts. I'm sure you'll find the story very entertaining.
Guess you're all stuck with us commie socialist Nazi fascist fucksticks after all.