3/5 rule:    from Negro President, by Gary Wills p 2:   "The negotiated agreement "(necessary for the Constitution to be accepted in the South) "stated that each slave held in the United States would count as three-fifths of a person--the so-called federal ratio--for establishing the representation of a state in the House of Representatives (and consequently in the Electoral College, which was based on the House and Senate numbers for each state in Congress."

As you know, slavery was the original sin of the US.

So, as a Federalist pointed out, a planter with 100 slaves could be considered as having sixty votes, while a Northerner without slaves but with equal or greater property had only one vote. This gave the slave states huge power.    For various reasons stemming in large part from this, between Washington's election and 1850, slaveholders controlled the presidency for 51 of the 62 years.



More later if I have time.