How real people fight fascism.
Known popularly as a great doomed romance film, Casablanca deals in subjects much more important and I would say the romance element is secondary to how the fascism of the 30s and 40s destroyed and affected the lives of everyday people and how they were able to fight back in small and big ways.
It might be hard to find someone who doesn't know the story of this film even 80+ years later so I won't talk too much about it and focus more on some things the film says about the time it was created and sadly, the time we find ourselves in now.
Ilsa is not some femme fatale leading Rick along in Paris. Her husband was murdered, she thinks, in a Nazi camp and when she finds out otherwise she leaves Rick to leave Paris without her to save his life and to get back to hers as the Nazis take over the city. Rick's bar in Casablanca is a den of corruption and despite his cynical outward nature he is constantly doing things for the betterment of the refugees who are there waiting, hoping to get to the United States and safety. In today's world, America has become a country to escape from having not learned the lessons, or maybe learned the wrong lessons, from WWII and the folly of runaway nationalism and authoritarianism. Almost everyone in the movie is a victim of the political situation and Rick quietly tears up Nazi cheques and helps in small ways to get people to safety as he wallows in self pity over the loss of Ilsa. He does not bow to the authorities or to the rich tycoons that come into the bar and despite his claims of neutrality, his distaste for them is obvious.
In the scene where the bar goers drown out the nazis singing Die Wacht am Rhein with La Marseillaise, all the different nationalities singing together until the Germans return to their seats in defeat. This is a lesson that diverse groups coming together can make the bullies back down, even if just for a little while. It does and always has brought tears to my eyes. It did so even before I knew many of the extras and indeed some of main cast were actual refugees of the war. Their tears as they sing are real.
At the end Rick and Ilsa both realize that their lives and love are dwarfed by the events of the world at large but both are heading to do something about it exchanging personal sacrifice for the greater good. The war was full on at this point and who would win was not known but the message that everyone has to do what little they can to fight evil is a good one.
This film was successful but no one making it thought it would be the iconic, influential film it became. It's message to do what you can for the cause is reflected in how the movie itself did much more than than anyone at the time could have imagined. Lets all try and do the same.