Casablanca
I mean it's Casablanca you know what I'm rating it. It's a classic and it's easy to see why. For one, the script was amazing with some iconic quotes. "Round up the usual suspects" for example.
Basically, it follows the story of a man who owns a nightclub in Casablanca learning to stop being a centrist and stand up for people he cares about. If you look at when this came out, yeah this was definitely made to convince Americans to care about WW2. Even still, that is a theme that can be carried over to other conflicts later on, like Vietnam, Palestine, etc.
It's really cool this film made a statement like this in a romance film, too.