In his book, The Making of Casablanca, Aljean Hurmetz writes that the movie has been viewed as an allegory of America's movement from neutrality to war. "casa" means house and "blanca" white while Rick represents a reluctant President Roosevelt who finally involves the U.S. in World War II.
This ambivalence is also a trait of postcolonialism. After the colonial period of England and France, there emerged societies with contradictions and split loyalties. Rick's bar holds company with people of these traits. The most glaring example occurs in the scene in which the French girl enters the bar with the German soldier, leading the Frenchmen to sing an audacious "La Marseille," drowning out the German national anthem begun by the soldiers. Throughout the movie, Rick denies any loyalties repeatedly: "I stick my neck out for nobody." His ambivalence extends itself to life itself. When Ilsa asks him if she will see him that night, Rick replies, "I never make plans that far ahead."
Another characteristic of the postcolonial is an alienation from his native land. Rick certainly has this as he feels nothing for America. Postcolonials often have had a traumatic experience that causes this alienation and erode's the individual's identity. Of course, Rick's traumatic experience that the viewer knows of is his rejection by Ilsa during the Paris defeat in World War II. In his saloon, he attaches himself to no one, repeating his phrase "I stick my neck out for nobody," but also disavowing any politics. He tells a German officer, "Either lay off politics or get out." In another scene Rick tells others, "Your business is politics; mine is running a saloon." Cynical throughout the movie, Rick claims to have come to Casablanca--in the desert--for "the waters." This cynicism is born of Rick's perception of the falsity of the political authorities.
It is only his love for Ilsa that rekindles Rick's love of country. Victor Laslo congratulates Rick, "Welcome back to the fight. This time I know our side will win."