What prompted this speech by sumner to congress in 1856?

Charles Sumner was prompted to deliver his famous "Crime against Kansas" speech because the circumstances under which the pro-slavery movement had manipulated the Kansas convention in order to come out with a pro-slavery group of constituents who would then determine that Kansas would enter into the union of the United States as a slave state, which would undermine and set off balance views that were contrary to what Charles Sumner aligned himself, with the abolitionist movement to eliminate or abolish slavery.