What Ron Paul is saying is that the United States is not a ligitmate nation and he wants to break up the Union. Hitler also wanted to break up the United States and give the Southwest back to Mexico. Neo Nazi and KKK militia's still want to break up the US and create some kind of whites only homeland. These guys are guys who claim the Lousiana Purchase was illegal and want to give Hawaii back to the Emperess of Hawaii. These are the kind of peole Ron Paul pals around with, he is a Leftist who wants to destroy this country.
As far as the Civil War is concerned Lincoln did not stop states from seceeding. In fact Jefferson Davis was sworn in as president of the Confederacy before Lincoln was sworn in a president of the United States. The Confederacy was free to set any kind of trade policy they wanted but they chose to fire on Ft Sumter and started the Civil war.