Final answer:
The North opposed counting slaves towards the representative population because it would grant the Southern states more political influence without slaves having voting rights, leading to the Three-Fifths Compromise.
Step-by-step explanation:
The North did not want slaves to count towards the representative population because doing so would give Southern slaveholding states disproportionate political power in the House of Representatives and the Electoral College. This would happen despite the fact that slaves had no voting rights and were not considered citizens with their own interests to be represented. During the Constitutional Convention, this concern led to the creation of the Three-Fifths Compromise. This compromise counted each enslaved person as three-fifths of a free individual for the purpose of both representation and taxation, somewhat mediating the power imbalance. However, the compromise still granted Southern states significant additional representatives based on their enslaved population even though this group was not granted the privileges of representation or the ability to participate in the political process.