A corrective the next time someone holds up John Wayne as an exemplar of American manhood and courage. From Mark Harris' “Five Came Back: A Story of Hollywood and the Second World War”: 

Since the war had started, [director John Ford] had watched with increasing contempt as John Wayne had made and broken one vague commitment after another to join up. Wayne’s star had risen since his breakthrough in Stagecoach and he was now in constant demand in Hollywood; he talked earnestly of going into the army or the navy, but always right after the next movie. In the spring, when Ford point-blank offered Wayne a spot in Field Photo, he had declined, and he declined again when the offer was reiterated in August. ... Wayne never would enter the war; he would fulfill his commitment to the armed services by doing a USO tour, getting no closer to combat than the starring role in Republic’s The Fighting Seabees. Ford found his behavior reprehensible.

Cf. this recollection from Gore Vidal, who also went to war. According to Scott Eyman in his biography “John Wayne: The Life and Legend," Wayne's lack of service haunted the man until the end. 

One of the many John Wayne inspirationals floating around the Web.