25. It is unlikely, however, that this variant would
 cause any redically new or different political or military
 responses from the USSR or Communist China. Their main
 efforts, is before, would be to provide the necessary
 support to Hanoi to maintain a flow of supplies and a strong
 air defense. The Chinese would probably reinforce their
 anti-aircraft and logistical forces along the rail line
 from Hanoi to Dong Dang. During this bombing campaign it
 is also possible that the USSR would provide more effective
 weapons for the defense of North Vietnam.
 26. The principal danger of a greater Chinese military
 involvement would probably arise from the bombing of all
 the airfields. The North Vietnamese would try to continue
 air defense operations for as long as possible. But the
 time might come when the conditions of the fields made
 operations too difficult or virtually ineffective. At this
 point, the North Vietnamese might want to transfer operations
 to bases in China.
 27. We think the Chinese would be highly reluctant to
 accept the risks to their own territory from such operations.
 But if the North Vietnamese did insist on operating out of
 Chinese bases, the Chinese probably could not afford to
 rebuff them. Thus, there is a chance that the Chinese would
 -14-
 
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