Casablanca has been subjected to many different readings. Semioticians account for the film's popularity by claiming that its inclusion of a whole series of stereotypes paradoxically strengthens the film. Umberto Eco explained:
Thus Casablanca is not just one film. It is many films, an anthology. Made haphazardly, it probably made itself, if not actually against the will of its authors and actors, then at least beyond their control. And this is the reason it works, in spite of aesthetic theories and theories of film making. For in it there unfolds with almost telluric force the power of Narrative in its natural state, without Art intervening to discipline it.
...When all the archetypes burst in shamelessly, we reach Homeric depths. Two clichés make us laugh. A hundred clichés move us. For we sense dimly that the clichés are talking among themselves, and celebrating a reunion.
Eco also singled out sacrifice as one of the film's key themes: "the myth of sacrifice runs through the whole film." It was this theme which resonated with a wartime audience that was reassured by the idea that painful sacrifice and going off to war could be romantic gestures done for the greater good.
Koch also considered the film a political allegory. Rick is compared to President Franklin D. Roosevelt, who gambled "on the odds of going to war until circumstance and his own submerged nobility force him to close his casino (partisan politics) and commit himself—first by financing the Side of Right and then by fighting for it." The connection is reinforced by the film's title, which means "white house".
Harvey Greenberg presents a Freudian reading in his The Movies on Your Mind, in which the transgressions which prevent Rick from returning to the United States constitute an Oedipus complex, which is resolved only when Rick begins to identify with the father figure of Laszlo and the cause which he represents. Sidney Rosenzweig argues that such readings are reductive, and that the most important aspect of the film is its ambiguity, above all in the central character of Rick; he cites the different names which each character gives Rick (Richard, Ricky, Mr. Rick, Herr Rick, boss, and so on) as evidence of the different meanings which he has for each person.