Linebacker II- Strategic Bombing for a Tactical Objective

As the US public became increasingly weary of the seemingly unending US involvement in Vietnam, the Nixon administration negotiated with the North Vietnamese to secure an exit from the war without throwing our South Vietnamese allies to the wolves. Negotiations had been mostly fruitless for a long time. The North Vietnamese knew time was on their side and sought to drag the negotiations out as long as possible, with the eye to either achieving  their goals on the battlefield, or through concessions at the negotiating table.

The NVA first tried to achieve military victory with their Easter Offensive begun on March 30, 1972. Ironically, after years of training, organizing and equipping both  our forces, and the Army of the Republic of Vietnam (ARVN) as a counter-insurgency force, we faced what was in effect a conventional army in a conventional offensive action. It is quite likely only the prompt application of massive US airpower that stemmed the tide of this assault. First, tactical US airpower supported friendly forces on the ground. Secondly, US forces began the first sustained air campaign against North Vietnam since President Johnson had suspended Rolling Thunder in 1968.  Operation Linebacker was a large scale interdiction effort designed to interrupt the NVA’s ability to supply its armies in their offensive. For the first time in the war, B-52 bombers were sent against targets in North Vietnam. But there were still restrictions. The B-52s were only used in the southern parts of North Vietnam. The Rules of Engagement may have been far more lax than under the Johnson era, but they were still quite a number of targets that were off limits. The areas of Hanoi and Haiphong (the port serving Hanoi) were off limits to the big bombers.

Still, Linebacker was a successful campaign. With the failure of the NVA offensive, the North Vietnamese began for the first time to seriously negotiate. By the late fall of 1972, the US and North Vietnam had reached a consensus on what a cease fire would look like. The problem was, the South Vietnamese government wasn’t directly involved in the talks. When the US presented the framework to the South Vietnamese government, they balked. When the US went back to the table to modify the agreement, the North Vietnamese walked out. President Nixon was faced with a crisis. The next US Congress would be enter session on the 3rd of January, 1973. It was quite likely that if there was no signed peace agreement, the Congress would simply cut off funds for our efforts in Vietnam, in effect, ending our involvement by the power of the purse. The NVA would then not be constrained by any agreement whatsoever.  Nixon was increasingly desperate to pressure the North into signing the agreement. Frustrated by the North’s intransigence, he turned to airpower to sway them.

A massive aerial assault on North Vietnam would be unleashed. And for the first time, the B-52s of SAC would be going downtown. Hanoi and Haiphong would be their destination.  Over 200 B-52s, based in Thailand and at Guam, would be assigned to the campaign, in addition to the hundreds of Air Force and Navy tactical aircraft available.

There were two models of B-52 available. The older B-52D model was optimized for the conventional high altitude strike mission. With most responsibility for the nuclear role removed, it’s bomb bays had been modified to carry larger numbers of conventional 500lb bombs. Between the bomb bays and the external wing racks, a B-52D could carry 108 five hundred pound bombs. Further, having been used in Southeast Asia for years, their electronic warfare systems were optimized to counter the Vietnamese SA-2 missile system, with extremely powerful jammers.

B-52D during an Arc Light mission over South Vietnam

The other bomber available, the B-52G was the first of the Stratofortresses that had been designed with the low level nuclear strike mission in mind. And since it still had that primary nuclear strike role, it had not been modified to carry larger internal bomb loads, nor were its jammers optimized for the SA-2. In a low level mode, a more nuanced approach to jamming would be taken. But the enormous numbers of anti-aircraft artillery guns in North Vietnam dictated that they would have to use a high level approach, just as the B-52D models would. Their less powerful jammers would leave them somewhat more vulnerable to SAM fire.

B-52G at Anderson AFB, Guam, during Linebacker II

Air operations against North Vietnam were the responsibility of the 7th Air Force. Navy aircraft came under the aegis of Commander, Task Force 77, reporting to the Commander, US Pacific Command. But the B-52s all belonged to the Strategic Air Command at Offutt Air Force Base in Nebraska. This lack of unified command would have consequences. 7th AF, under the direction of the White House, designated targets, and coordinated with TF77. But the actual planning of mission for the B-52s was directed by SAC. The senior leadership of SAC had spent 30 years planning a campaign against the Soviet Union. But they had little practical experience with the air defense network of North Vietnam. SAC was concerned more with North Vietnamese fighters than the Surface to Air Missiles (SAM). During the first Linebacker operations, North Vietnamese fighters had been very aggressive, and SAC was convinced they would be the primary threat. But that ignored the extensive losses the North had incurred during those operations.  President Nixon initially authorized a three day campaign, dubbed Operation Linebacker II, to begin on 18 December, 1972.

SAC’s orders led to the use of “corridor” tactics, in which a stream of bombers would approach the target by the same route and altitude, while escorts laid down chaff, Wild Weasels suppressed SAMs, electronic warfare planes jammed radars, and fighters covered them from North Vietnamese interceptors. With only three days strikes authorized, SAC pressed for a maximum effort, with 129 bombers launched on the first night. The primary targets that night were airfields that housed the MiGs of the North. The problem with the corridor tactic was that it took a long time to get that many bombers over the various targets. Losses on the first night were three B-52s, roughly 2.5% of the force, heavy, but acceptable.

Artist depiction of Linebacker II

The problem is, you can’t remain predictable in war without the enemy finding an effective counter to your operations. The second night saw 93 bombers over North Vietnam. Only about 20 SAMs were launched, less than a third of the previous night, and no bombers were lost. SAC was sure its tactics were vindicated.

But the North Vietnamese quickly adapted. On the third night, 99 bombers went after power plants, rail yards, and petroleum storage sites. And it was a bloodbath. The North Vietnamese knew when and where the strike was coming. With only 34 SAM launches, they shot down eight B-52s, four G models, and four D models (one of these four managed to limp to Laos before it crashed). An 8% loss rate, even with the massive support from tactical aircraft, was simply unacceptable. SAC was stunned. But the crews were not. From the moment the first strike planning had come down from on high, they had railed against what they saw as outdated, unimaginative planning. Mission planning from people half a world away from the conflict, with little or no experience in the theater of operations, had the crews livid. Time and again, they begged to be allowed to plan their own missions. Time and again, SAC rebuffed their pleas.

Nixon extended the operation beyond the initial three day authorization. SAC, reacting to the heavy losses of the previous night, grounded the Guam based bombers. Only the Thailand based B-52D models, those best equipped with jammers, would go north. The greatly reduced numbers of bombers would shorten the time needed to hold open a corridor. But SAC still insisted on the same tactics that had proved disastrous the night before. Of 30 bombers that went over North Vietnam that night, two were shot down, a 6% loss rate.  That was still far too heavy. Losses that high would mean that in only a few more days, the heart of SAC’s bomber force would be gutted. Losses of aircraft and personnel were bad enough. But from SAC’s perspective, the loss of prestige was even worse. If they couldn’t defeat the North Vietnamese, the entire premise of strategic bombing would be called into question.

7th Air Force, controlling the tactical aircraft in theater, did what it could to help. Its F-111 all weather strike aircraft were pulled off interdiction targets, and instead directed against airfield, and more importantly, against SAM sites that had played merry hell with the bombers. By closely coordinating the timing of these F-111 strikes, they could ensure the SAMs most likely to interfere with the bombers were too busy defending themselves to do anything else.

A painting of an F-111A during the Linebacker II operation

Further, strikes in the Hanoi area were curtailed. Instead, targets in the slightly less defended Haiphong area were struck. Missions on the 22nd, 23rd, and 24th of December, numbering about 60 aircraft each, saw no losses from the bomber force. An errant string of bombs on the 22nd struck a hospital near a petroleum storage site (and not far from an airfield) causing a furor, but operations continued.

But bombing around the periphery of Hanoi wasn’t going to force the North Vietnamese back to the negotiating table. Almost every worthwhile target was in the Hanoi metropolitan area.

The campaign stood down for Christmas. But operations would resume on the night of the 26th. And  changes to the tactics were in hand. SAC, having presided over the disastrous losses earlier in the campaign, finally released local B-52 commanders to plan the missions they would execute. Importantly also, the Guam B-52s had been hurriedly modified with extra jammers to allow them to operate over North Vietnam again.

The raid on the 26th was a massive one. 120 B-52s, supported by 113 tactical aircraft headed north. Most infrastructure targets had been pummeled so the attacks concentrated on the air defense system. SAM sites, radar sites, and airfields would bear the brunt of the attack.

More importantly, corridor tactics had been abandoned. Rather than streams of bombers flying in file down a highway in the sky, several raids would converge from all around the compass, at different altitudes, all at the same time. In 20 minutes, the raid would come, bomb, and leave. The North Vietnamese, accustomed to the previous tactics, were unable to cope with the sudden onslaught of so many aircraft at once, from so many directions. One B-52 was lost over the target, and one crashed on return to Thailand, for a far more acceptable loss rate of 1.6%.  A 60 plane raid the next night also saw the loss of two bombers, a 3.2% rate, heavy, but acceptable.

The last two nights of raids were both of 60 aircraft each. No losses were incurred among the bombers. On the last night, in addition to the 60 bombers up north, 30 G models conducted “Arc Light” missions further south.

After the 29th of December, the raids were suspended.  The raids were stopped for two reasons. First, the North Vietnamese had agreed to return to the negotiating table. Secondly, there were few remunerative targets left for the bombers to strike. Contrary to popular belief, the B-52s weren’t just laying a carpet of bombs across all of North Vietnam. Instead, great pains were taken to only strike militarily significant installations and infrastructure. North Vietnam was such a backwards nation, there just weren’t a lot of those targets.

With the end of Linebacker II, and with Nixon’s message to the South that the agreement would be signed, with their blessings or over their objections, a cease fire was signed. The air campaign against North Vietnam was over. For over 8 years, the US had conducted a campaign marked by indecisiveness, micromanagement, a deeply flawed understanding of the enemy, and an inability to properly plan and execute a decisive air campaign.

The political issues surrounding the campaign and its effects are outside the scope of our discussion, but the Air Force certainly learned a number of lessons about how to plan and execute a decisive campaign.  Less than 20 years later, the Air Force would find itself pitted again against a complex, integrated air defense system. And it would prevail in a matter of weeks, not years. Still, not all lessons gleaned were correct. The disastrous attempts to put entire squadrons of early F-16s over Baghdad early in Desert Storm showed that learning is a continuing process.

It’s is impossible to know if a Linebacker II style campaign early in the war would have achieved the same goals as it did in 1972. But it is clear that the North Vietnamese were deeply impressed with the campaign when it did come.