Answer:
well...
Step-by-step explanation:
1) The Missouri Compromise of 1820, The Compromise of 1850, and The Kansas-Nebraska Act of 1854.
2) They were doomed to fail. enslavement was never going to be a sustainable practice in a modern democratic country. But the institution was so entrenched in the United States that it could only be resolved by a Civil War and the passage of the 13th Amendment.