If one views the overall American product, one must include the well-known "Yankee Doodle" (a British-authored song, but adopted by our own troops as their signature piped tune); Stephen Foster's "Oh, Susanna," "Way Down Upon the Suwanee River," and "Old Black Joe"; to "Battle Hymn of the Republic" as well as "Away Down South In Dixie"; the cowboys' songs "Red River Valley" and "The Streets of Laredo";thence to "When Johnny Comes Marching Home" that was carried over to WWI, enhanced by George M. Cohn's "Over There" (a Tin Pan Alley, NOT a Broadway derivative); after WWI "Bye, Bye, Blues" (1925), "Bye Bye Blackbird" (1926), "Let A Smile Be Your Umbrella" (1927), "Moonglow" (1933, made again popular by Kim Novak and Bill Holden's dance in Picnic, 1955); and a whole bunch of other Big Band tunes 1926-1956 that were not Broadway-related: "Chattanooga Choo Choo," "In The Mood," "Don't Get Around Much Anymore," etc.; and vocals "Paper Doll" (Mills Brothers), "White Christmas" (Berlin-1940/Crosby-1942, best-selling single ever).
Another of mine, which I was 8 and learned at my WWII sweetheart Aunt Elaine's knee about 1944, "Don't Fence Me In"(Bob Fletcher/Cole Porter, made famous by Roy Rogers and Kate Smith). After the war, I fell in love with my 5th grade schoolmate Mary Spangler, and learned "I'm Looking Over A Four-Leafed Clover" and sang it until she jilted me (about 2 weeks later), followed by Vaughn Monroe's plaintive "I Guess I'll Get the Papers And Go Home"; not long before the Christmas time tune "Walking in a Winter Wonderland," written by a tuberculosis invalid in a Scranton, PA sanitarium (1934, NOT a B'way stage play).
It's been 81 years of my love for the world of music, from my Mom's sweet alto voice singing lullabies to the English -authored spiritual song "Abide With Me," which I sang as a member of the SPEBSQSA Hornell, NY "Maple City Chorus" in the final concert at the Chautauqua Assembly Auditorium for the 1971 season, and which I would like included at my funeral service; and maybe Simon and Garfunkel's "Like A Bridge Over Troubled Waters."
I appreciate your loyalty to the repertoire that you are endorsing as exclusive; but, my FRiend, to me it is way too narrow, even quite pinched, to account for the great musical wealth of my polyglot American Heritage, touched only across the peaks by the 90-minute program in which I directed the Auburn, NY "Lakelanders Chorus" in the city's 1976 outdoor Sesquicentennial Celebration, singing one great American tune after another, of which only a few were Broadway-derived.
Note also, that our discussion has not even considered the non-verbal works of John Philip Sousa, or Aaron Copeland, or George Gershwin ("Rhapsody in Blue"); only three of the vast list of America's classical musicology, or of the loose Pennsylvania school of gospel musicians (Ira Sankey, P. P. Bliss, Charles Tindley, and others) that changed the nature of the evangelistic Christian musical environment: freshly crafted psalms, hymns, and spiritual songs, filled with Biblical doctrine, admonishment, wisdom, and love of the Christ of Calvary; which audience is now my almost exclusive focus.
(Not intended to offend you, just a few comments on the scope of "What is a great American song?" not so much as "What is a great American songbook?")
“Chattanooga Choo Choo” comes from a Hollywood musical called “Sun Valley Serenade”, which featured Glenn Miller and teh Orchestra, Tex Benecke, and the Modernaires. (That’s the version usually heard.)
My mother was one of the world’s greatest Big Band fans, especially Miller. I won a bunch of Big Band albums — and even more Broadway show albums (a record cabinet full of them.)
“White Christmas” coems from Irving Berlin’s “Holiday Inn”. which also gave us “Easter Parade.” A musical.
I never said the Great American Songbook is exclusively Broadway, but it is very heavily so. Many things we don’t think of as Broadway songs are. Even more are written by Broadway composers.