Oh sure, those at the Constitutional Convention could have insisted slavery end and the Constitution would never have been written. The Southern States would have simply walked out of the Constitutional Convention.
billofrightsinstitute.org
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The Framers made a prudential compromise with slavery because they sought to achieve their highest goal of a stronger Union of republican self-government. Since some slaveholding delegations threatened to walk out of the Constitution if slavery was threatened, there was a real possibility that there would have been separate free and slave confederacies instead of the United States. The free states would have lost all leverage over the slave states to end slavery if they had separated. The Framers had to create the Union with the institution of slavery but built a regime of liberty that they hoped would lead to slavery’s ultimate extinction.
The specific clauses of the Constitution related to slavery were the Three-Fifths Clause, the ban on Congress ending the slave trade for twenty years, the fugitive slave clause, and the slave insurrections. However, the Constitution only very obliquely referred to slavery and never used the words slave or slavery because the Framers were embarrassed by the institution. They believed that slavery was morally wrong and would die out, and they did not want that permanent moral stain on the document. Interestingly, they avoided the word slave and referred to slaves as persons.
Also don’t forget the states had to ratify the Constitution before it could take effect. If the Constitution had banned slavery or freed all slaves in 10 years, the Southern states would have rejected the Constitution at their conventions.