As part of Operation Prairie, the 3d Battalion, 4th Marines attacked North Vietnamese Army installations along Razorback Ridge in the Quang Tri province on September 22. It was the hardest fighting of the seven-week-old campaign. Helicopters assisted ground forces throughout the fighting, now and then bombing the jungle to clear the way for the Marines’ advance and resupplying the men each night to leave them free of extra gear as they searched the hills for the North Vietnamese Army. By early October North Vietnamese Army Division 324B had abandoned the fight and slipped back across the demilitarized zone into North Vietnam.

Operation Prairie was part of the Johnson administration’s new show of force in Vietnam. During Operation Rolling Thunder in July, U.S. planes had begun bombing oil depots around large North Vietnamese cities, including one target only three-and-a-half miles from the capital of Hanoi. Three thousand aircraft were engaged through August and September, making seven hundred strikes each day against storage facilities, factories, army convoys, and jungle bunkers. The President signaled he was stepping up pressure and would rely less on negotiations. “The communist leaders,” he said, “no longer really expect a military victory.” Despite the bombardment and heavy losses among the North Vietnamese, communist troops and arms moving south along the Ho Chi Minh Trail increased dramatically. The North Vietnamese Army’s ability to elude Marine forces by crossing the demilitarized zone during Operation Prairie would eventually lead to bombing of the DMZ itself.

—Nathan Ward