<P> The crews had been told that the North Vietnamese would rush hundreds of personnel to the drop site and remove the "soap" before the rainfall that was necessary to activate the chemicals . On the last mission, the third aircraft, commanded by Captain John Butterfield, was seriously damaged by ground fire . Although he managed to land at Chu Lai, the aircraft was a total loss due to a warped wing spar . For his actions on that day, Capt . Butterfield received the Silver Star medal . It was decided that the experiment didn't justify the risk, and the mission was officially cancelled . </P> <P> On the ground, the CIA and the Royal Lao Army had initially been given the responsibility of stopping, slowing, or, at the very least, observing the enemy's infiltration effort . In Laos the agency began Operation Pincushion in 1962 for that reason . The operation evolved into Operation Hardnose, in which CIA - backed Laotian irregular reconnaissance team operations took place . </P> <P> In October 1965, General Westmoreland received authorization to launch a U.S. military cross-border recon effort . On 18 November 1965, the first mission was launched "across the fence" and into Laos by the MACV - SOG . This was the beginning of an ever - expanding reconnaissance effort by MACV - SOG that would continue until the operation was disbanded in 1972 . Another weapon in the American arsenal was unleashed upon the trail on 10 December 1965, when the first B - 52 Stratofortress bomber strike was conducted in Laos . </P> <P> A commonly occurring historical perspective concerning the interdiction effort tends to support the campaigns (regardless of their failure to halt or slow infiltration) due to the enemy material and manpower that it tied down in Laos and Cambodia . This viewpoint pervaded some official U.S. government histories of the conflict . John Schlight, in his A War Too Long, said of the PAVN's logistical apparatus: </P>

Why did the us bomb the ho chi minh trail