“I get mad these days,” Duke once said, “when I see our boys there getting killed and maimed, and people back home aren’t behind them.” John Wayne didn’t just talk the talk — he put himself in harm’s way to stand behind our troops. In 1966, he traveled to the front lines of Vietnam, slogging through muck and monsoon rain to meet the men of the 502nd and 327th Infantry in Dak To, and on June 20, the 3rd Battalion, 7th Marines at Chu Lai. A sniper narrowly missed him during the visit — a reminder that he didn’t seek comfort, but connection. “I never heard complaints—from privates up to generals,” he said after returning home. One soldier he never met, however, would leave a lasting mark on his life: Captain Stephen P. Hanson of Burbank, CA. The Marine had sent a photo to his family captioned “Me as John Wayne,” just before his Sea Knight helicopter was shot down over Laos on June 3, 1967. Duke wore Captain Hanson’s POW bracelet from that point on, and kept in touch with the family for...