Actually, 13 States actually did secede from the "perpetual Union" of the Articles of Confederation (Article XIII of same, already cited and quoted above) which was never supposed to be superseded or seceded from.
But they did -- they had to, to form the United States of our present Constitution. Madison discussed this quandary in the later numbers of The Federalist Papers.
The mechanism of secession was a sovereign act of the People of each State, to-wit, ratification of the Constitution.
But then, your interlocutor Michael Zak, the manifold revenant zombie of FR, has had this explained to him many, many times before, when he was posting here as Grand_Old_Partisan and two or three other screennames. But we are expected to accept his proposition in posting this thread, that "that was then, but this is now."
Most of the neo-Confederate loons who post on Free Republic are really Democrat provocateurs, trolling to discredit conservatives.
Now the states did not secede from the Articles. There was nothing to imply that the Articles were to be the eternal government of the Union it created.
Not only that but the mechanism for creating the new form of government was placed in action by the Congress governing the Confederation. It shows the difference between a legal change of governmental form and and illegal and ex-constitutional insurrection.
Ratification was by the American People gathered in convention IN the states. States were explicitly prevented by Congress from making that decision.