If I am not mistaken secession was simply declared illegal by the US Supreme Court ruling after the war. Anti-secession clauses were written several state Constitutions again after the War also.

But, Anti-secession clause can be repealed and the United States Supreme Court has reverse its own rulings several time in the history of that court.

No one claims that secession was a good thing for the country as we now have come to know it? But, Was it legal at the time, has always been the question? From the references, which you have cited, it would seem that this theroy was widely taught at West Point.

It would seem that as I have purposed in the past that there was some other larger principal involved in the entire senior staff of the United State Army resigning and casting their lot with the Southern Confederacy.

No one has ever answered my question, a while back, about other than Col. Phillip St George Cooke and Gen. Winfield Scott, what other Officer was left in the United States Army with the rank of Colonel or higher after Col Robert E. Lee resigned on April 17th 1861? It would seem that Lee was offered the post as commander of the United States Army because he was the "last man standing", so to speak.

If this text was being taught during the time those men, who were the senior staff of the Army in 1860, such as Gen Samuel Cooper, Joe Johnson, Albert S Johnston, P.T.G. Beauregard, and R. E. Lee, were at the Academy, its teachings could well have been a part of their decision making process.