On Mallory Square in Key West, Florida, tourists slurp sugary rum drinks through curvy straws and snap photographs of the sunset. Circus performers walk on stilts, swallow swords, and juggle flames. Among the chaos, a man cradles a guitar like a newborn in his shaky hands, and belts out the lyrics to "The Star Spangled Banner." Men with gold watches pitch him the occasional dollar, but no one spares a second to notice the crossed rifles painted on his pale skin, the Purple Heart pinned to the collar of his white shirt, or the scar beneath his right eye from the bullet that buzzed him as he slithered snail-like through the lush vegetation and mountains of Afghanistan. And no one  notices the track marks radiating up his too-skinny arms or the roar of his unfed belly.