Article 6, Clause 2
James Madison, Notes on Nullification 1835--36Writings 9:606--7
A political system which does not contain an effective provision for a peaceable decision of all controversies arising within itself, would be a Govt. in name only. Such a provision is obviously essential; and it is equally obvious that it cannot be either peaceable or effective by making every part an authoritative umpire. The final appeal in such cases must be to the authority of the whole, not to that of the parts separately and independently. This was the view taken of the subject, whilst the Constitution was under the consideration of the people. It was this view of it which dictated the clause declaring that the Constitution & laws of the U. S. should be the supreme law of the Land, anything in the constn or laws of any of the States to the contrary notwithstanding.
The Founders' Constitution
Volume 4, Article 6, Clause 2, Document 43
The University of Chicago Press
The Writings of James Madison. Edited by Gaillard Hunt. 9 vols. New York: G. P. Putnam's Sons, 1900--1910. See also: Federalist
Easy to print version.