Article 1, Section 2, Clause 3
Document 21
St. George Tucker, Blackstone's Commentaries 1:App. 189
1803This mode of ascertaining the number of representatives, and the inseparable connection thereby established between the benefits and burthens of the state, seems to be more consonant with the true principles of representation than any other which has hitherto been suggested. For every man, in his individual capacity, has an equal right to vote in matters which concern the whole community: no just reason therefore can be assignéd why ten men in one part of the community should have greater weight in it's councils, than one hundred in a different place, as is the case in England, where a borough composed of half a dozen freeholders, sends perhaps as many representatives to parliament, as a county which contains as many thousands; this unreasonable disparity appears to be happily guarded against by our constitution. It may be doubted indeed how far the apportionment of the numbers, as it respects slaves, is founded upon the principles of perfect equality; and if it be not, it may be a further question whether the advantage preponderates on the side of the states that have the most, or the fewest slaves amongst them; for, if on the one hand it be urged, that slaves are not in the rank of persons, being no more than goods or chattels, according to the opinion of the Roman jurists, and consequently not entitled to representation, it may be answered that the ratio of representation and taxation being the same, this additional weight in council is purchased at an expence which secures the opposite party from the abuse of it in the imposition of burthens on the government. On the other hand, it must be remembered, that the two fifths of this class of people who are not represented, are by that means exempted from taxation. An exemption which probably took its rise from the unprofitable condition of that proportion of the number of slaves.
The Founders' Constitution
Volume 2, Article 1, Section 2, Clause 3, Document 21
http://press-pubs.uchicago.edu/founders/documents/a1_2_3s21.html
The University of Chicago Press
Tucker, St. George. Blackstone's Commentaries: With Notes of Reference to the Constitution and Laws of the Federal Government of the United States and of the Commonwealth of Virginia. 5 vols. Philadelphia, 1803. Reprint. South Hackensack, N.J.: Rothman Reprints, 1969.