Which of the following had the most impact on the Civil War?
A. Whether a new state or territory should enter the Union as Free or Slave
B. The role of the Mason-Dixon Line in the Missouri Compromise
C. Tariffs on goods imported and exported between the South and Britain
D. Preston S. Brooks’s attack on Charles Sumner in the Senate
It would be "Whether a new state or territory should enter the Union as Free or Slave" that had the most impact on the Civil War, since the North was strongly against the spread of slavery, while the South was in favor of it.
