Race relations
It was refreshing in a movie from 1950 see a person of color in a role that is not a servant or a train porter. The character of Wesley is fully realized as a man who works hard, has a family and a home, and is somewhat the moral conscience of Harry. Harry continually tries to keep Wesley out of his more underhanded activities, whether because it was to protect Wesley from what could happen or just to not have to feel his judgment of Harry's bad decisions.
That scene at the end with Wesley's son looking for him at the dock while all around him everyone is worried about Harry...heartbreaking and powerful.