The unspoken tremor in most wartime movie romances is that the picture needs to address the feelings of couples separated by war. It's not just whether they will both survive, but whether love and desire can overcome the temptations that come with separate lives. There's another element at work (vital to romance and the age of censorship in the movies) which is that desire may mean the most when it cannot be consummated: the wish for intimacy is so intense because the act is forbidden or impossible.
In Casablanca, we assume that Rick (Humphrey Bogart) and Ilsa (Ingrid Bergman) had a good deal of sex in Paris, but in their awkward reunion in north Africa, sex is not renewed. Rather, the triangle of Rick-Ilsa-Victor (Paul Henreid) must contemplate the ultimate selection of just two of them to go forward. And we know now what Rick's decision is, even if in our enlightened time we may ask whether Ilsa shouldn't have been doing some of the deciding. But the romantic or erotic energy is sublimated in the most impeccable cause of all – the war effort. Rick forsakes Ilsa as part of his new commitment to the fight against fascism.
Casablanca stands for movie romance in great part because it is hardly true to life. It won the best picture Oscar and seemed to be history coming to life – it opened just after the allies had occupied the real Casablanca. In fact, divorce and infidelity rates increased rapidly during the war. But Casablanca reassured us all; it promised that honour was intact.
