The World: Border Recessional: The Return of Con Thien

THE Leathernecks who set up the McNamara line—the string of forward posts just below Viet Nam's Demilitarized Zone—used to describe their shell-pocked bases as "machines for killing Marines." The wry echo of Le Corbusier's famous line was morbidly appropriate. To counter enemy infiltration into South Viet Nam, the outposts had to be close to the DMZ—and therefore within easy range of Communist artillery in North Viet Nam and of mortars and rockets illegally positioned inside the six-mile-wide zone.

Last week, in a further Vietnamization of the war, the last of the bases that...