They didn't even try to address the issue and it nearly tore the country apart. Political cowardice often leads to bloody wars. But I was agreeing with you that the Constitution in its nascent form was woefully inadequate in protecting everyone's rights.
The issue was an obvious deal breaker during the age. There is no way that any semblance of national unity could be formed and slavery abolished in the 1780s. Even those founders that strongly supported a more centralized government while opposing slavery in principle didn't touch this political third rail.
In every real sense, there was no viable way to get both a nation that included the 13 colonies AND abolish slavery. With Britian circling in the waters like a hungry shark, any reduction in size would have been seen as weakness. If not for the majority body, at least for the minority.
They doubled down on national viability rather than purity of principle. Had they not, in all likelyhood the US would have failed as a nation.
Looking through the prism of history, it's not easy to see that slavery had yet to become an entrenched part of the economy for all states in the 18th century. Yes it would have been difficult, but much less so before it grew into an issue that would lead inevitably to secession. My point is, they didn't even try. And let's face it, it's because they didn't want to.
The issue was property. Regardless of how vital slaves were to the economy of a given state, they were a considerable property investment by individuals who owned them. The abolishment of slavery would nullify that investment and cause massive turmoil within each state in which it occurred. Abolishment would have caused damage to the individual states that had significant slave populations.
'Looking through the lens of history', the 'United States' was barely more than a notional concept in the 1780s. These representatives were for their state first. And for a nation only if it benefitted their states. Abolition would have caused significant damage to most of the southern states.
Even without abolition, the constitution barely passed. There is virtually no chance of ratification of the constitution with such a provision in it. While a significant danger to the States collectively and individually if they didn't unify more tightly.
The issues that motivated the constitutional convention and the writing of the Constitution were issues of practicality, functionality and security. Slavery was not the motivation. The issues that motivated the writing of the cosntitjution dominated. The issues that didn't motivate its writing were largely subordinate.
My angle is a little different here. The 13% black population in this country today and all the problems we're dealing with today because of it is because slavery became an industry with demand from southern states being accommodated by northern states bringing in hordes of them by ship. Had Lincoln's wishes prevailed, we would have shipped every one of them back and become a better, stronger nation because of it. Wise man, that Lincoln. I see why you guys love him so much.
Lincoln's plan was indeed to create a nation of freed black slaves. A nation that was in fact created. Lincoln, being a product of his age and experience, didn't think that the black and white man could live together in harmony. He stated, rather bluntly, that the whites would take advantage of the blacks and dominate them as the blacks lacked the capacities that whites possessed.
Lincoln's views changed over time, specifically after he was exposed to black men like Fredrick Douglas. Douglas was extremely well educated, articulate, thoughtful, and insightful. His many conversations with Lincoln convinced the President that his views of the black man may not be universal. Shortly before his murder, he advocated making citizens out of 'exceptional' blacks and any former slave that fought in the civil war.
For one who didn't think any black should ever be a citizen, this was a huge change in position. One of the things I liked about Lincoln....is that his positions could change based on the evidence.