[skepsel]

The North was not slave free, per the census of 1790 only Maine and Massachusetts had no slaves.

New York was 6% slave, the rest of the North had 1% or less per state, see below:

https://teachingamericanhistory.org/resource/the-constitutional-convention-free-and-slave-populations-by-state-1790/

[Republican Wildcat]

Slavery was very sparse in all of those states and outlawed not long afterward.

Nice revisionist history, however, and responding to arguments not being made.