Yankee Doodle Dandy is a 1942 American biographical musical film about George M. Cohan, known as "The Man Who Owned Broadway". It stars James Cagney, Joan Leslie, Walter Huston, and Richard Whorf, and features Irene Manning, George Tobias, Rosemary DeCamp, Jeanne Cagney, and Vera Lewis. Joan Leslie's singing voice was partially dubbed by Sally Sweetland. Wikipedia
George M. Cohan: It seems it always happens. Whenever we get too high-hat and too sophisticated for flag-waving, some thug nation decides we're a push-over all ready to be blackjacked. And it isn't long before we're looking up, mighty anxiously, to be sure the flag's still waving over us.