Singer-songwriters Joe Ely, Jimmie Gilmore, Terry Allen and Butch Hancock were high school buddies in Lubbock, Tex. When the Washington Project for the Arts brought them here last fall to do research for the "War and Memory: In the Aftermath of Vietnam" exhibit, the four found the names of several old classmates on the shiny black wall of the Vietnam Memorial. Friday night at the Museum of Natural History, the four singers repaid WPA with an hour-long song suite about the state of post-Vietnam America. At least four of the songs were written especially for the occasion, but all of them brought the sprawling subject into sharp focus through the eyes of some down-to-earth west Texas cowboys.

Ely, sporting a black-and-red cowboy shirt and playing rock 'n' roll electric guitar, was the most charismatic performer. His unaccompanied version of "Letter to L.A." was a chilling ballad of unrequited love (or unrequited patriotism); the three others joined him for his brand-new "Who's in Charge," a rocking challenge to authority. The skinny, boyish Gilmore sounded a bit like Jimmie Rodgers on his unaffected memory song, "Down in My Hometown."

The professorial Allen hunched over his piano and sang short, vicious satires from his epic "Youth In Asia" project. The evening's biggest revelation was the grizzled Hancock, who wore a beatnik cap, cowboy boots and a harmonica holder and sang mesmerizing, Dylanesque fables about veterans, angels, motorcyclists, Indians and the Statue of Liberty.