A case that originated in St. Louis, over one man, had an impact on the entire nation. Dred Scott lost the case in the Supreme Court in 1857 and died before the Civil War began. Chief Justice Roger B. Taney's ruling (set a national already hotly debating slavery to the edge of war.
Scott, a slave, sued for freedom from his owner after he moved to Illinois (a free state) and then back to St. Louis. The fight went back and forth in court, with Scott winning a decision in 1850. That decision was appealed, and eventually reached the Supreme Court. Taney wrote that Scott couldn't sue, because he wasn't a citizen -- no black person (even a free black person) was a citizen. He further ruled that Congress shouldn't have passed the Missouri Compromise, because they lacked the power to bar slavery in territories.