Question: What was the pro-slavery group called that Silas Soule clashed with?
Sentence (from "Silas Soule"): Silas Stillman Soule (July 26, 1838 – April 23, 1865) was an American abolitionist, Kansas Territory Jayhawker, anti-slavery militant, and a friend of John Brown and Walt Whitman.
Relevant evidence: Yes