Actually, if eleven states seceded today, the United States government maybe inviolation of international law to the military militias of several states against others to bring them back into the Union. The United States, a permanent member the United Nations, is a signer of the United Nations charter and treaties. By law these treaties trump the U.S. Constitution. It specifically states...

United Nations Declaration on the Rights of Indigenous Peoples

Article 3
Indigenous peoples have the right to self-determination. By virtue of that right they freely determine their political status and freely pursue their economic, social and cultural development.

Article 4
Indigenous peoples, in exercising their right to self-determination, have the right to autonomy or self-government in matters relating to their internal and local affairs, as well as ways and means for financing their autonomous functions.

Article 46
1. Nothing in this Declaration may be interpreted as implying for any State, people, group or person any right to engage in any activity or to perform any act contrary to the Charter of the United Nations or construed as authorizing or encouraging any action which would dismember or impair, totally or in part, the territorial integrity or political unity of sovereign and independent States.

Adopted by General Assembly Resolution 61/295 on 13 September 2007

Over the past sixty years the United Nations has made its goal to stop internal civil wars across the globe as a means to stabilize world peace. The secession movement of 1860-61, if it happened today, would play out very differently.

_________________________
David Upton