Someone commented an intriguing scenario on another thread; what if Liston had to carry out a mob hit on Sullivan? They meet in a dark alleyway with nobody else in sight, who comes out alive?
I would say Liston. While I’m sure John Sullivan was an extremely tough man who was in a fair number of brawls, Liston was on the streets when he was barely a teenager and ended up being a collector for the mob. Spent a little time in the can as well.
Liston was known to carry a high caliber revolver and was no stranger to dark ally events given he was a collector for the mob. I see this bushwackin in favor of Liston.