With those words, Police Prefect Captain Louis Renault (Claude Rains) became the hero of Casablanca (1942). Yes, I know that Richard Blaine (Humphrey Bogart) thumbed his nose at the Nazis, sacrificed his love for Ilsa (Ingrid Bergman) to help Victor Lazlo escape the Germans, and shot the villain, Major Strasser (Conrad Veidt). I also know that Captain Renault had "no convictions," blew "with the wind," and was only a "poor, corrupt official." Nevertheless, he was the hero because, if not for his actions, there would have been no happy ending.
When the Casablanca police arrive at the airport, Victor and Ilsa's plane is taxiing down the runway, Rick stands near the dead body of Major Strasser hiding a smoking revolver in his pocket. The officers report to Captain Renault, who has witnessed the shooting. In his most official voice, Captain Renault states that "Major Strasser's been shot." Then, as the audience waits for him to arrest Rick, with only the slightest pause for a look at Rick, Renault gives the command to "Round up the usual suspects." At that point, the theater audience inevitably cheers, and only the hero gets cheers.
profile on Rains posted by Classic Movie Digest. Like one of my other favorite actors, Basil Rathbone, Rains was equally adept as good guy (if rarely leading man) or villain.