“We may safely rely on the disposition of the state legislatures to erect barriers against the encroachments of the national authority.”
That reliance was misplaced. The encroachments of the national authority are legion, and the state legislators are incapable of erecting the needed barriers. That incapacity is a result of a technical error in Article V, requiring 2/3 for a quorum. Correct the error, and the erection of the barriers can begin.