What issue developed in regard to the states that would be made from the louisiana purchase

The issue that developed in regard to the states that would be made from the Louisiana Purchase was whether to allow the states to become slave-bearing states or free states.

Bear in mind that before this, there were equal numbers of slave bearing states and free states. So the issue was they could not make one state at a time because then it would not be equal in terms of slave states and free states.