In a famous essay on Casablanca Umberto Eco wrote "When all the archetypes burst in shamelessly, we reach Homeric depths. Two cliches make us laugh, but a hundred cliches move us because we sense dimly that the cliches are talking among themselves and celebrating a reunion." I think Eco's language is unnecessarily condescending, but he does have a point about the movie: Casablanca's characters and situations are consistently archetypal. The movie isn't about a love triangle between three people, it's about a love triangle between the portrait of cynicism, the portrait of idealism, and a long suffering wife trapped between the two poles.
The Good German is Steven Soderbergh's reworking of the Casablanca story, but this time set in a more realistic world, with more realistic consequences. The story starts in Berlin right after the end of the war and right before the Potsdam conference that established the post-war map of Europe. It's a setting that lends itself to a complex mixture of emotions: all of the rubble that still litters the city streets creates a mood of defeat and cynicism, but the promise of an end to the bloodshed also creates pockets of optimism. There's also a lot of fear in the air, because another world war between the Soviets and the U.S. could be just around the corner if the conference isn't settled to everyone's satisfaction. It's a much darker backdrop for a love triangle than the mythic Casablanca that Bogart lived in.
Similarly, the love triangle in the Good German is much more complicated, too. You have Jake, played by George Clooney, an American journalist played who wants to believe that the U.S. is going to do the right thing at Potsadm, but who doesn't completely trust what he's hearing from the generals he meets. Then you have Lena, played by Cate Blanchett, a formerly proud woman who has been reduced to prostitution to survive, who has seen too much suffering for her own good. Finally, you have Emil, played by Christian Oliver, a scientist who helped the Nazis build missiles, who has the most complicated set of emotions of any character in the movie. All three of them are practical in ways that the characters in Casablanca weren't: their focus is on personal survival as much as it is on doing the right thing, and they've made very painful sacrifices to survive this long. They're going to make more sacrifices before the movie is over, too.
I don't want to describe the Good German as if it was only a riff on another classic. Yes, Soderbergh has constructed his film so that it will comment on Casablanca, but he's also using it to interrogate history. World War 2 is not presented in this movie as a "good war" where the good guys triumphed over the bad guys - this is a film that is very conscious of the fact that choosing sides between Hitler and Stalin was not necessarily easy, and that the U.S. entered the war for it's own reasons, not all of which were altruistic. There's a reason why the film is called "The Good German" - because it's asking hard questions about the nature of responsibility and guilt, two themes which are eternally thorny, but which are particularly hard to untangle when it comes to hard fought wars.
There's a cynicism to the way that the Good German portrays the U.S. that can be a little shocking if you aren't prepared for it. One of the only characters in the Good German who isn't really analogous to anyone in Casablanca is Tobey Maguire's Tully, who looks cornfed but has a sadistic streak. Tully speaks to America's opportunistic handling of the war - to the fact that the U.S. rebuilt Europe not just because it was the right thing to do, but also because it was profitable. Tully's blatant crassness is a little jarring given how understated the other performances are, but I think his character is a good addition to the story because he provides another perspective in the film's central themes.
Still, as a person that is more interested in art than history, the parts of the Good German which speak to me the most are the ones which are explicitly riffing on Casablanca. For example, the Good German's framing and cinematography are spot on homages, but the Good German uses fewer and stronger lights to create more of a stark contrast between the figures in the overly lit foreground and the desperately underlit background. (Which is, of course, perfect, given how much more extreme it's world is.) It's a movie whose look both evokes and mocks the cleanliness of a bygone era.
That duality is ultimately what makes the Good German feel so compelling to me. This film is more than a wolf in sheep's clothing - it's a film which is trying to walk the line between being a wolf and a sheep in such a way that we have to ask ourselves questions about both wolves and sheep. I think that the Good German is interested in Casablanca because it's a well made and beloved movie, but also slightly repulsed by it, since it almost functions as propaganda; it certainly reinforces the notion that one side of the war was noble, and the other was evil. I think that the Good German is interested in the Potsdam Conference because it produced a fairly equitable deal, especially compared to the treaties that ended the first World War, but at the same time it's also repulsed by the way that the victors were so quick to be self serving; all of the participants had no qualms about drafting unrepentant Nazi scientists for their own nuclear bomb programs. Those are not easy tensions to reconcile, and examining them is not going to leave you with the same level of comfort that you have at the end of Casablanca. But you know, sometimes when the story ends with everyone standing in the rain watching their hopes leave on a plane it should feel tragic, not just bittersweet.