In 1854, the Missouri Compromise was repealed by the Kansas-Nebraska Act. Three years later the Missouri Compromise was declared unconstitutional by the Supreme Court in the Dred Scott decision, which ruled that Congress did not have the authority to prohibit slavery in the territories.
Answer:
The most obvious way was through open rebellion. In 73-71 BC the gladiator Spartacus famously led an uprising of thousands of slaves in central Italy, formed an army that defeated several Roman legions, and at one point threatened Rome itself.
