When Max Steiner was asked to write the score for Casablanca, he was told to use the popular song “As Time Goes By” as a love theme for the two main characters, Rick and Ilsa. But as Mervyn Cooke tells us in his book, A History of Film Music,
Steiner apparently disliked the song and wished to replace it at a rather late stage with one of his own: since this would have involved reshooting several of Ilsa’s scenes, the displeased studio executives prevented his doing so on the pretext that Ingrid Bergman had already changed her hair style for her next film.
If Steiner felt stuck with the song, he certainly didn’t show it. In the film, after Sam plays the song for Ilsa, it becomes an integral part of Steiner’s orchestral score. More than that, Steiner skilfully transforms the song to depict Rick and Ilsa’s changing emotions at various stages in their relationship. A quick look at four scenes will demonstrate this in a film music analysis.
Scene 1: Rick Sees Ilsa Again
As Sam plays “As Time Goes By” for Ilsa, Rick overhears and tells him to stop playing the song. At this point, he sees Ilsa for the first time since she abandoned him in Paris. The shock he feels here is palpable, in large part due to Steiner’s music, which enters on a sudden loud chord (called a “stinger” in films) and states the tune of “As Time Goes By” over a dissonant chord. This chord lasts for some time, as though the shock of seeing Ilsa has frozen Rick’s emotions into an intense state. Gone from this version of the song is its romantic, nostalgic tone.
Watch the scene here, starting from 1:20:
Scene 2: Rick’s Flashback to Paris
As Sam plays “As Time Goes By” at Rick’s request, Rick slips into a flashback of his time in Paris, when he fell in love with Ilsa. These were certainly happier times for Rick, and the music reflects this with a jaunty version of “As Time Goes By” that focuses on sweet writing in the strings, major chords, and does not even hint at any minor keys like the original version.
View the scene here from about 0:57:
Scene 3: Rick at the Train Station
In this scene, Rick is devastated as he reads a letter from Ilsa that tells him that she can never see him again. We don’t see much of this on his face, but the music here is unmistakable: it is a heart-wrenching version of “As Time Goes By”, now entirely in a minor key and scored with rolling timpani, cymbal crashes, growling brass, and soaring strings. The harmony also emphasizes the diminished-seventh chord, a traditional symbol of tragedy in tonal music.
Watch the scene here (but please excuse the foreign subtitles):
Scene 4: The Final Goodbye
Rick convinces Ilsa to board the plane out of Casablanca with her husband Laszlo instead of with Rick himself. While this will prevent Rick and Ilsa from ending up together, Ilsa realizes that Rick is doing it out of love for her. And so the music cooperates, sounding a version of “As Time Goes By” that not only returns to most of its original harmonies, but is also slowed down and set mostly for strings. With these changes, Steiner’s setting of the song is one of the film’s most romantic, and appropriately enough, he saves it for what is perhaps the most touching expression of love in the entire film.
View the scene here (with its many famous lines):