Missouri compromise of 1820 • slavery banned in the louisiana territory north of the 36°30’ parallel • slavery allowed in the louisiana territory south of the 36°30’ parallel • missouri joined the union as a slave state what other agreement was a part of this compromise? the fugitive slave law was enacted to gain the support of southern states. kansas was given the choice whether to join the union as a free or slave state. a higher tariff was introduced to satisfy manufacturers from northern states. maine joined the union as a free state to keep the total of free and slave states equal.