Signal To Noise: How the Electoral College Is Tied to Slavery and the Three-Fifths Compromise

"The idea of a simple popular-vote election struck fear in delegates from slaveholding states because while their states boasted large populations, much of the populace was comprised of enslaved black people who could not vote. By contrast, northern states had smaller populations with a greater number of eligible voters (read: white, male, and generally property-owning)."