This is what our founders intended: The Union was formed by the voluntary agreement of the states; and these, in uniting together, have not forfeited their nationality, nor have they been reduced to the condition of one and the same people. If one of the states chooses to withdraw from the compact, it would be difficult to disapprove its right of doing so, and the Federal Government would have no means of maintaining its claims directly either by force or right.

"But as the plan of the convention aims only at a partial union or consolidation, the State governments would clearly retain all the rights of sovereignty which they before had, and which were not, by that act, EXCLUSIVELY delegated to the United States." - Alexander Hamilton

"A national government is a government of the people of a single state or nation, united as a community by what is termed the 'social compact,’ and possessing complete and perfect supremacy over persons and things, so far as they can be made the lawful objects of civil government. A federal government is distinguished from a national government by its being the government of a community of independent and sovereign states, united by compact." -Blacks Law Dictionary