[BroJoeK]

HandyDandy: "The death knell for slavery in those Colonies began precisely with the creation of the US Constitution.
The northern States began immediate steps for the eventual abolition of slavery concurrent with the creation of the Constitution."

If you check out this link, you'll see that gradual abolition actually began soon after the Declaration of Independence:

1. 1777 -- Vermont
2. 1780 -- Pennsylvania
3. 1783 -- Massachusetts
4. 1783 -- New Hampshire
5. 1784 -- Connecticut
6. 1784 -- Rhode Island
7. 1787 -- Northwest Territories (Ohio, Indiana, Illinois, Michigan, Wisconsin)

That left New York (1799) and New Jersey (1804) which had not yet started gradual abolition by the time of the constitutional convention in 1787.

As of the 1790 census, only Vermont and Massachusetts reported no slaves, and as of 1850, only New Jersey in the Northeast reported some slaves.
In the meantime, Southern slaves grew from about 700,000 in 1790 to nearly 4 million in 1860.

In the 1790 census, of 700,000 total slaves, about 40,000 lived in the North = 6%.
By 1860 of 4,000,000 total slaves, only 35 total lived outside the South = 0.001%

[HandyDandy]

I will concede your point. But then that means that this statement by our FRiend jeffersondem, “And of the nine northern slave states, only nine voted to include slavery in the Constitution” is somewhere out in la la land.