I don't believe that the bombing up to the present has significantly reduced, nor any bombing that I could contemplate in the future would significantly reduce, the actual flow of men and materiel to the South.69
North Vietnam's ability to sustain its war effort and continue to provide supplies to the South hinged directly upon its support from China and the Soviet Union, a factor that Johnson was constantly aware of but, understandably, unwilling to deal with militarily. However, before 1965, Russian and Chinese military assistance to North Vietnam was relatively insignificant, and no official pledge had been made. It was Johnson's own actions against the North that secured forthcoming support for Hanoi.
When Washington's retaliatory attacks following the February 1965 Pleiku incident coincided with Soviet Premier Alexei Kosygin's visit to Hanoi, the Russians pledged substantial military and economic assistance.70 Within several weeks, the first sams were arriving in Haiphong.71 By the end of 1965, North Vietnam would have received 60 of these advanced missile launching platforms, and would boast more than 250 by the end of 1967.72 Soviet history expert I.V. Giaduk wrote that:
The Pleiku incident and U.S. retaliation destroyed what was left of Moscow's hope to avoid internationalization of the conflict in Vietnam. As a result the Soviet Union was forced to set aside its policy of propaganda and noninvolvement and plunge into a war with unpredictable consequences.73
When the Chinese followed suit, it was clear that Johnson's bombing of the North had - despite his grave fears - fully internationalized the war, increasing the political dangers of escalation and the immediate threats to U.S. pilots. Although when Rolling Thunder began the North Vietnamese air defence system had no jet aircraft, no missiles, fewer than 20 radar installations, and a mere handful of anti-aircraft guns, within two years support from the U.S.S.R. gave North Vietnam what Tucker has called “the most sophisticated air defence system in the world.”74 On any given month in 1967, the North Vietnamese used their 10,000 anti-aircraft guns to fire more than 25,000 tons of flak at American planes, and launched hundreds of missiles from more than 25 sam battalions.75 By the end of this year, the North Vietnamese Air Force possessed 80 operational MiG fighters, including the most recent MiG-21.76 Worrying statistics of this magnitude were clearly available at the time. Sullivan wrote in 1968 that Northern air defence was “one of the most intensive systems yet devised,” more concentrated than anything U.S. pilots faced during the Second World War over Germany.77
This Soviet and Chinese military support was put to deadly use. From 2 March 1965 to 31 October 1968, the duration of Rolling Thunder, 922 U.S. planes were lost over North Vietnam.78 Such losses were disproportionately high compared with losses over the South. In 1966, for example, though only 30% of American sorties were flown over the North, 60% of U.S. losses were incurred there.79 A report in May 1967 from the Office of the Secretary of Defense stated that the air campaign against “heavily defended areas” cost the United States one pilot in every 40 sorties.80 Given that a tour of duty in Vietnam could last for 200 missions,81 the long-term odds were stacked against U.S. strike pilots. Clearly, Soviet and Chinese military support was instrumental in North Vietnam's ability to defend itself and hurt the Americans.
The North Vietnamese resistance effort, however reliant on external support, was nonetheless ultimately determined by its own citizens and leadership. The country was able to capitalize on its low-tech advantages over the United States in order to counter American technological dominance. To counter U.S. high explosives in the form of air-dropped mines or direct air attack, villagers found suspicious objects and poked them with long sticks from behind bamboo shields; they dragged logs and chains to set off mines and foul sensors; they created false truck convoys with fake headlights; and they constructed dummy supply dumps and bridges.
82Camouflage was raised to an art.83 To aggravate the U.S. further, the geography of the area was such that it made movement almost impossible for aircraft to control.84 As Sullivan reported, this situation was worsened by North Vietnam's “primitive”85 transportation system. Earl Tilford, published in Armed Forces and Society, emphasized the uselessness of American technological superiority in the face of North Vietnam's sound strategy of resistance.
Cluster bombs, napalm, herbicide defoliants, sensors dropped along the Ho Chi Minh Trail to monitor traffic and aid in targeting, gunships, and electro-optically guided and laser-guided bombs all promised much, and while some delivered a great deal of destruction, in the end technologically sophisticated weapons proved no substitute for strategy.86
