However, the more involved the United States gets, the more involved Blaine gets with helping his love and in the end he helps Lund escapes. This is very similar to the way the United States helps the Allies to escape the atrocities of the Nazis. To me the final line of the movie, when Blaine says to a French friend "I believe this is the beginning of something beautiful," sums up the United States intentions in the War. I think these words symbolize the U.S.' decision to open a second front in France and help...

To me the film's ability to symbolize such a crucial part in the worlds' history so eloquently makes it a classic as well.
A also believe Casablanca is a classic because I believe the actors are so ahead of their time. The chemistry that Bogart and Bergman have may still have never been duplicated in a love story to this day. The combination of the acting, symbolism and the number of different storylines within Casablanca makes it one of the most classic films of all time.