Article 1, Section 9, Clause 1
James Madison to James Monroe10 Feb. 1820Writings 9:22
I have been truly astonished at some of the doctrines and deliberations to which the Missouri question has led; and particularly so at the interpretations put on the terms "migration or importation &c." Judging from my own impressions I shd. deem it impossible that the memory of any one who was a member of the Genl. Convention, could favor an opinion that the terms did not exclusively refer to Migration & importation into the U. S. Had they been understood in that Body in the sense now put on them, it is easy to conceive the alienation they would have there created in certain States; And no one can decide better than yourself the effect they would have had in the State Conventions, if such a meaning had been avowed by the Advocates of the Constitution. If a suspicion had existed of such a construction, it wd. at least have made a conspicuous figure among the amendments proposed to the Instrument.
The Founders' Constitution
Volume 3, Article 1, Section 9, Clause 1, Document 22
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.