Missouri was important to the South that it be admitted to
the Union as a slave state because it could tip the balance between pro-slavery
and anti-slavery states in the Union. This
had become a very sensitive issue. To
solve this dilemma, it came up with the Missouri Compromise of 1820. Under this compromise, Congress was allowed
to admit Missouri as a state but it also admitted the Main to the Union as
well. This kept the balance between the
states and maintained the peace.