another gentleman says, it was intended to restrain Congress from
interfering with emigration from Europe.

These constructions cannot both be right. The gentlemen who have
preceded me on the same side, have advanced a number of pertinent
arguments to settle the proper meaning of these words. I, sir,
shall not repeat them. Indeed, to me, there is nothing more dry
and uninteresting, than discussions to explain the meaning of
single words. In the present case, I will only refer to the
authority of Mr. Madison and Judge Wilson, who were both members
of the Convention, and who gave their construction to these
words, long before this question was agitated. Mr. Madison
observes, that, to say this clause was intended to prevent
emigration does not deserve an answer. And Judge Wilson says,
expressly, it was intended to place the new States under the
control of Congress, as to the introduction of slaves. The
opinion of this latter gentleman is entitled to peculiar weight.
After the Convention had labored for weeks on the subject of
representation and direct taxes--when those great men were like
to separate without obtaining their object, Judge Wilson
submitted the provision on this subject, which now stands as a
part of your Constitution. Sir, there is no man, from any part of
the nation, who understood the system of our Government better
than him; not even excepting Virginia, from whence the gentleman
from Georgia (Mr. Walker) tells us, we have all our great
men.[578]

Madison wrote on the same question that year in a letter to Monroe:

I have been truly astonished at some of the doctrines and
declarations to which the Missouri question has led; and
particularly so at the interpretation 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 had in the State conventions, if
such a meaning had been avow