Between the North (anti-slavery) and South (pro-slavery).
Boarder Ruffians raided the anti-slavery town of Lawrence, Kansas. Which led to John Brown an abolitionist to execute 5 pro-slavery settlers. After this, both sides fought back and fourth throughout the year, it became known as "Bleeding Kansas".
During Bleeding Kansas, murder, destruction became took place in Eastern Kansas and Western Missouri
In Washington D.C., Charles Sumner got beat u with a cane by Andrew Butler because he disagreed with what was going on with "Bleeding Kansas"
It made people question whether popular sovereignty was a good idea or not