How so?
At the Constitutional Convention, the slave states wanted to count their slave population in apportioning Members of Congress, even though the slaves were not state citizens and could not vote. The slaveholders, IOW, counted their slaves as full human beings.
The free states didn't want the slaves to count at all - because the free states ALSO knew the slaves were full human beings, and were afraid that if they allowed the slavemasters extra votes in the House that slavery would never be ended.
In order to obtain ratification of the Constitution, a compromise was necessary. The slave states were allowed to add representatives by enumerating the slaves as part of their population, but the number of slaves (and Indians not taxed) had to be multiplied by 0.6, reducing their impact because they were not participating in the political community.