“Actually, it was free northern states that wanted blacks to be counted as 3/5ths of a person for apportionment purposes. This issue was completely separate from disenfranchisement of blacks.”
I thought it was the other way around, the free states wanted the slaves to not count as a person (with respect to apportionment) and the slave states wanted them to be counted as a full person. Being counted counted as a full person gave greater voting power to the slaveholders. The 3/5ths thing was a compromise, but it’s possible that slavery could have been eliminsted earlier had the slaves been counted as zero. I’m google-less at the moment, but someone jump in here and correct me if I’m wrong.
You’re right. The southern states wanted to count the slaves in when it came to determining the number of Congressmen a state would have, but not allow the slaves to vote. The three-fifths measure was a compromise — one that still gave extra power to the voters of slaveholding states.