Increases in bombing were just as useless, clouding any remaining perception in North Vietnam that America may actually have wanted peace. After an escalation of bombing, Assistant Secretary of State William Bundy reported that “our bombing actions had left the Soviets - and by implication, Hanoi - in complete doubt as to what our intentions and views really were.”32 The very fact that bombing pauses were always followed by more bombing led to a profound lack of trust between Hanoi and Washington. American negotiators in Paris often “ran into suspicions”33 from Northern representatives that the United States would just increase the bombing again, a claim that was very hard to dispute when it had been proven time and again with recent events. It became clear to all involved that whatever was done with bombing, escalation or pause, the diplomatic situation worsened.
Rolling Thunder's powerlessness to bring about a diplomatic response from the North was compounded by politically-driven tactical limitations on bombing operations from Washington. Key civilians in the administration, most notably McNamara,34 shied away from the abrupt and concentrated strategy of aggression advocated by the Joint Chiefs of Staff, fearing that it would provoke a wider conflict with China or the Soviet Union. After all, the world had been brought to the brink of nuclear war during the Cuban Missile Crisis only four years before, and the need to keep situations from escalating out of control was still ripe in memory.
Cornelius Sullivan's 1968 study, published just after Rolling Thunder's conclusion, explained that the possibility that China and the Soviet Union might “react strongly” to a concentrated, fast, and heavy bombing campaign in the North was “without doubt a compelling argument” against such action.35 This view is still widely held. In 2000, Larry Addington wrote that unlimited conventional bombing in North Vietnam would have “risk[ed] war with the People's Republic of China, if not the Soviet Union,” and pointed to Beijing's public warnings that it would not remain indifferent to North Vietnam's situation.3637 Clearly, the Johnson administration felt the need to retain a degree of control over the operation. Additionally, the less discriminate bombing advocated by the Joint Chiefs would turn much world opinion against the United States.
Washington's control over the bombing was, accordingly, very tight. In fact, as Sullivan explained in 1968, the White House had maintained “direct and immediate control over almost every aspect of the air war in the North,”38 bypassing Military Assistance Command, Vietnam (macv) entirely39. This was evident from the start of the campaign, formalized on April 27, 1965, when McNamara indicated that the President would retain control over the operation's “tempo and scope.”40
It cannot be known if China and the Soviet Union would have responded with military force had the Joint Chief's more aggressive plan been implemented. What can be analysed without much speculation, however, are the direct effects of Washington's policy on Rolling Thunder's effectiveness. Johnson and McNamara imposed a policy of steady escalation on the strikes,41 so severely limiting the targets that could be hit at the start of the operation that that Maxwell Taylor, former Chairman of the Joint Chiefs of Staff and ambassador to South Vietnam at the time, exclaimed early on “I fear that to date Rolling Thunder in their eyes has merely been a few isolated thunderclaps.” 42 At the onset of the operation, days - sometimes weeks - would elapse between strikes. Throughout 1965, the government in Hanoi was still more under threat of pressure than it was under any real stress, and certainly not in any environment likely to force its diplomatic hand.
Washington limited the targets for Rolling Thunder geographically as well, to be broadened only exceedingly slowly. Indeed, Johnson boasted that he wouldn't “let those Air Force generals bomb the smallest outhouse ... without checking with me.”
43 Air Force historian John Correll wrote that, at the start of the campaign, North Vietnam's real strength around Haiphong and Hanoi was “not touched, not even threatened… a strange way to begin a war.”
44 For a period of months, all authorized targets were below the 19th parallel. The bomb line then was extended northward to targets below the 20th parallel, and, by mid-1966, into the Red River Delta.
45 In July 1967, 169 out of 436 “Primary Target Systems” in North Vietnam were still "Not Authorized” for attack.
46 Only by August 1967 were American aircraft authorized to attack targets near Hanoi and Haiphong.
47 By this time, the North Vietnamese knew what to expect, and understood how to deal with air attack.
