My point was that that little law in the US Constitution would not have deterred a people who were set on slavery to the point of seceding from the US and forsaking that very same Constitution.
A group of people who so objected to the Constitution that they wanted to return to the Articles of Confederation, would have, had the North bought all slaves, simply bought more slaves. If the North tried to impose the law on them, they would have seceded and said they no longer abided by the USC.
Compensated Emancipation, in every nation where it was tried, naturally included a moratorium on buying any new slaves which the slave-holders (having received their compensation) did actually respect.
The South was not so much "set on Slavery" as "set on the enormous monetary investment they'd made in Slavery" (money which had largely been paid to Yankee slave-traders in exchange for Slaves). Had a market-rate compensation been paid -- it's entirely probable that plantation owners, newly flush with Compensated Emancipation money and needing Labor, would have just hired black freedmen for cash wages rather than risk almost-certain imprisonment for importing new slaves.