318. Editorial Note
On May 27 the Joint Chiefs of Staff sent a memorandum to the Secretary of Defense recommending air strikes against the surface-to-air missile sites (SAM) being developed by Soviet technicians in North Vietnam, and against the Phuc Yen air base outside of Hanoi, where Soviet-supplied MIG fighters had recently been augmented by five IL-28 light bombers provided by the Soviet Union. (Washington National Records Center,RG 330, OSD Files: Lot 71 A 6489, Misc Sensitive Files, Vietnam 381) The Joint Chiefs considered that, although the offensive threat posed by the bombers was limited, “a failure to act could connote a [Page 694] weakening of US resolve to fulfill its commitment to defend Southeast Asia in the face of support of the DRV from the USSR.” (Ibid.) McNamara considered the proposal, and his marginal notations on the memorandum, although difficult to decipher, apparently indicate his concern over the risk of losses involved in the proposed operations, as well as the risk of an embarrassing international reaction to such attacks.
On May 27 McNamara sent a memorandum to the Director of Central Intelligence to ask for an intelligence assessment of the probable and possible Soviet, Chinese, and North Vietnamese reactions to the military operations proposed by the Joint Chiefs of Staff. (Department of State, Central Files, ORG 1 OSD-STATE) The CIA responded on June 2 with SNIE 10–6–65, “Probable Communist Reactions to Certain US Actions”, which concluded that the probable Soviet, Chinese and North Vietnamese reactions would be limited, and would not involve direct Chinese intervention nor a North Vietnamese invasion of the south. The Department of State dissented from the conclusion, and anticipated that the proposed attacks might prompt a response from air bases in mainland China. (Ibid., INR-NIE Files) The Department of State had indicated a similar concern on May 27 when Rusk called McNamara to discuss the rules of engagement governing immediate pursuit in connection with the Rolling Thunder bombing operations. Rusk asked that McNamara make it clear that pursuit operations against North Vietnamese aircraft include a caution against attacking air bases or other ground targets that were not on the designated target list. (Ibid., Rusk Files: Lot 72 D 192, Telephone Calls) McNamara returned the call on May 28 and indicated that instructions had been issued that no North Vietnamese SAM sites or air bases were to be attacked by U.S. aircraft. (Ibid.)
On June 2 McNamara sent a memorandum to the President in which he indicated that three senior U.S. military and diplomatic officials in Europe recommended against attacks on the IL-28 bomber base in North Vietnam (Document 325).