By legal secession or by nullification of laws the seperate and sovereign states disagree with
There is no process of legal secession under U.S. law except for the conflict resolution -in- the Constitution -- that is the amendment process.
The states are not completely sovereign under the Constitution. The Articles of Confederation had failed. When enough people realized that, something stronger was adopted. THAT was the Constitution with, as George Washington called it, "a coercive power". It was strong -enough- so that the government set up by the framers has existed from 1790 until today.
Walt
We disagree on what constitutes legal secession so we won't go there, but ignoring laws that the state disagrees with? Article VI says that the "Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." A state cannot nullify a law made under the Constitution and remain in the Union. If you can't live within the agreement then petition the other states to secede.