
Madison's notes (30 May 1787) http://avalon.law.yale.edu/18th_century/debates_530.asp
1780s, The Debates in the Federal Convention (1787)
Context: Mr. MADISON observed that whatever reason might have existed for the equality of suffrage when the Union was a federal one among sovereign States, it must cease when a national Govermt. should be put into the place. In the former case, the acts of Congs. depended so much for their efficacy on the cooperation of the States, that these had a weight both within & without Congress, nearly in proportion to their extent and importance. In the latter case, as the acts of the Genl. Govt. would take effect without the intervention of the State legislatures, a vote from a small State wd. have the same efficacy & importance as a vote from a large one, and there was the same reason for different numbers of representatives from different States, as from Counties of different extents within particular States.