Slight correction - it wasn’t for “voting”, because the slaves couldn’t vote regardless of how they were counted.
It was for population based representation in the House of Representatives.
Thank you. Yes, as soon as I posted I realized I had screwed up. The “3/5 of a person” was strictly for census.
But it was the North that reduced the personhood of a slave to 3/5, not the South.
FRegards,
LH