They made sure that the number of free states and slave
states were equal. This was bests seen
in the Missouri Compromise of 1820.
Under this compromise it stated that under
the Louisiana Purchase, the territory
north of latitude 36° 30' that makes up Missouri's southern boundary would be established
as free states and territory south of that line would be organized as slave
states. Main was also admitted as a free state as part of the compromise to maintain
the balance of Missouri's admission as a slave state.
