Why was the missouri compromise of 1820-1821 necessary?

The Missouri Compromise was an effort by Congress to defuse the sectional and political rivalries triggered by the request of Missouri late in 1819 for admission as a state in which slavery would be permitted. At the time, the United States contained twenty-two states, evenly divided between slave and free. I really really hope this helps you lots 

North korea has been ruled by dictator since 1948