When American intelligence detected the massive buildup of North Vietnamese troops that preceded the 77-day siege of Khe Sanh in 1968, Gen. William Westmoreland gave the base priority access to all American airpower in theater, leading to Operation Niagara and a “waterfall of bombs.”
Khe Sanh was the westernmost base in a strong of installations along the crucial Route 9 in late 1967. It was in the perfect position to block North Vietnamese Army forces and other fighters moving in from Laos or other NVA areas.
But Westmoreland believed that Khe Sanh was crucial to victory and worth heavy investment despite its relatively small size as home to one Marine regiment and 5,000 support troops. To ensure the Marines could hold out against anything, he ordered improvements to infrastructure on the base and the installation of thousands of remote sensors in the surrounding jungle.
By the first week of January 1968, sensors and reconnaissance data made it clear that the NVA was conducting a massive buildup in the area of the base. All indications were that the North Vietnamese wanted to recreate their success at Diem Bien Phu in 1954 when a prolonged siege led to the withdrawal of French forces.
Artillery rounds were stockpiled at the base and intelligence was collected. The intel cells were able to get a good idea of where Communist forces were concentrating forces, artillery, and command elements. They were also able to track tunneling efforts by the North Vietnamese trying to get close to the base.
And the North Vietnamese were able to get close — in some cases within a few thousand meters.
On Jan. 21, 1968, the North Vietnamese launched a simultaneous attack against Khe Sanh itself and some of the surrounding hills. Their massed forces would eventually number 20,000, more than three times the number of the 6,000 defenders.
The U.S., with a mass of intelligence and stockpiled weapons, went on the offensive against the North Vietnamese. Artillery shells shot out of the base against pre-identified targets, and a waterfall of bombs started pouring from B-52s.
The long-planned Operation Niagara II was underway. Over the following 77 days, strike aircraft from the Air Force flew 9,691 sorties and dropped 14,223 tons of bombs, those from the Marine Corps flew 7,098 missions and dropped 17,015 tons of bombs, while the U.S. Navy strike aircraft dropped 7,942 tons of bombs over 5,337 missions.
The heavy lifters were the Air Force B-52s who dropped 59,542 tons of bombs. The combined total of ordnance dropped around Khe Sanh by air was 98,721 tons, approximately 5,700 tons more than the total weight of the USS Enterprise.
Initially, the bombs were dropped relatively far from the base. The B-52s tried to stay three miles out, but the communists figured out the restrictions and moved their fighters in close, forcing the B-52s to operate closer to the base and making the ground pounders rely more heavily on strike aircraft and the AC-47 gunship.
Of course, not everything went smoothly for the Marines and their support. An enemy artillery strike by the North Vietnamese managed to hit the ammo dump, destroying 90 percent of the stockpiled rounds in a single hit.
Marines patrolling the jungle were also hard-pressed time after time. One patrol, conducted by two squads from Bravo Company, 1st Battalion, 26th Marine Regiment, on Feb. 25, 1968, was almost completely wiped out and became known as the “Ghost Patrol.” One survivor was taken captive and reported dead for nearly five years before he was released in a prisoner transfer.
While the leadership did entertain the idea of calling in tactical nukes of necessary, the efforts of the Marines on the ground — sometimes conducted by nearly starving troops after 11 weeks of rare resupplies — combined with the Herculean-levels of air support were enough to keep the North Vietnamese at bay.