The song was a First World War song sung by the Doughboys (the Yanks)thanks to the composer George M. Cohan. Looks like history is repeating itself ("we won't be back till the cruise missiles run out ... over there"). A rendition is heard on the 1960s anti-war movie "Oh What a Lovely War!" and the 1940s movie about George M. Cohan, starring James Cagney (the guy who never uttered the words "You dirty rat.").

Cheers, Brian