The issue of slavery at the Constitutional Convention was actually an issue about

The issue of slavery at the Constitutional Convention was actually an issue about how much control Congress or the central government of the United States has. Southern slaveholders did not want Congress to have control over the slave trade. They let Congress have control over all other forms of trade except for the slave trade. Many of the Northerners present at the convention did not want the Southern slaveholders to import more slaves from Africa. They did not want the African-American population to grow too big.