With its original title of Everybody Comes to Rick's still attached to the script, Casablanca was a tough sell with the studios. It was rejected nearly forty times outright (doesn't it seem like every major classic has a similar story?) before a deal was finally inked, but only once the title had been changed to the simpler, more elegant Casablanca.
And the timing couldn't have been more perfect. Right after the film was released, the Allied powers had started landing in northern Africa, making Casablanca a household name in the States. Now it wasn't only simple and elegant—it was relevant, too.
There may have been a little bit of wordplay at work there as well. "Casablanca" translates to "white house." If you subscribe to the whole idea that Rick symbolized American efforts to keep our head inside our collective shell, and Roosevelt's initial hesitation to get involved, in the European conflict, this theory makes perfect sense.
In present day, the "white house" could also be interpreted as "a complete inability to get anything done whatsoever." Which was Rick to a "T" for much of the movie.