Operation Linebacker II

Operation Linebacker II was a US Seventh Air Force and US Navy Task Force 77 aerial bombing campaign, conducted against targets in the Democratic Republic of Vietnam (North Vietnam) during the final period of US involvement in the Vietnam War. The operation was conducted from 18–29 December 1972, leading to several of informal names such as "The December Raids" and "The Christmas Bombings". Unlike the Operation Rolling Thunder and Operation Linebacker interdiction operations, Linebacker II, would be a "maximum effort" bombing campaign to "destroy major target complexes in the Hanoi and Haiphong areas...which could only be accomplished by B-52s." It saw the largest heavy bomber strikes launched by the US Air Force since the end of World War II. Linebacker II was a modified extension of the Operation Linebacker bombings conducted from May to October, with the emphasis of the new campaign shifted to attacks by B-52 Stratofortress heavy bombers rather than smaller tactical fighter aircraft.

"Peace is at hand"
On 8 October 1972, U.S. National Security Advisor Dr. Henry Kissinger and North Vietnamese Politburo member Le Duc Tho met in Paris. They were there to discuss new proposals by both nations, hoping to reach mutually agreeable terms for a peace settlement for the decade-old Vietnam war. Tho presented a new North Vietnamese plan which included proposals for a cease-fire, the withdrawal of American forces, and an exchange of prisoners of war. All three Vietnamese combatant governments: North Vietnam, the Republic of Vietnam (South Vietnam), and the Provisional Revolutionary Government of South Vietnam (PRG) would remain intact, as would their separate armies. Hanoi no longer demanded that South Vietnamese President Nguyen Van Thieu be removed from office, the U.S. did not have to cease its aid to the southern government and both Washington and Hanoi could continue to resupply their allies or forces on a parity basis. No new North Vietnamese forces were to be infiltrated from the north and the U.S. agreed to extend post-war reconstruction assistance to North Vietnam.

The new terms on the table also included the establishment of a National Council of National Reconciliation and Concord, a loosely defined administrative structure which was to work toward general and local elections within South Vietnam. Political power would be shared by three groups, the Saigon government, the PRG, and a "third force" group to be mutually agreed upon by the other two parties. Since it was to work by consensus, nothing could be accomplished by the new council without the agreement of President Thieu.

When the two sides convened again on 17 October, there were two main areas of disagreement: the periodic replacement of South Vietnam's American weaponry, and the release of political prisoners held by the Saigon government. The North Vietnamese had made significant modifications to their past negotiating position and were hurrying to get the agreement signed before November, believing that President Richard M. Nixon would be more willing to make concessions before, rather than after, the upcoming presidential election. Although there were still some issues to be finalized, Kissinger was generally satisfied with the new terms and so notified Nixon, who gave his approval to the settlement. The finalized agreement was to be signed in Hanoi on 31 October.

Kissinger then flew on to Saigon on the 18th to discuss the terms with Thieu. The South Vietnamese president was not happy with either the new agreement or with Kissinger, who he felt had betrayed him. Although Kissinger knew Thieu's negotiating position, he had not informed him of the changes made in Paris nor had his approval been sought. Kissinger "had negotiated on behalf of the South Vietnamese government provisions that he, Thieu, had already rejected." Thieu completely castigated the agreement and proposed 129 textual changes to the document. He went further, demanding that the Demilitarized Zone separating the two Vietnams be recognized as a true international border and not as a "provisional military demarcation line" (as had been stipulated in the Geneva Accords) and that South Vietnam be recognized as a sovereign state. The supreme irony, in the words of Stanley Karnow, had now arrived: "having fought a war to defend South Vietnam's independence, the United States was now denying its legitimacy."

Thieu then went one step further on 26 October and publicly released an altered version of the text that made the South Vietnamese provisions look even worse than they actually were. The North Vietnamese leadership, believing that they had been hoodwinked by Kissinger, responded by broadcasting portions of the agreement that gave the impression that the agreement conformed to Washington and Saigon's objectives. Kissinger, hoping to both reassure the communists of America's sincerity and convince Thieu of the administration's dedication to a compromise, held a televised press conference at the White House during which he announced "We believe that peace is at hand."

On 20 November, the South Vietnamese revisions and 44 additional changes demanded by Nixon were presented to the North Vietnamese delegation by Kissinger. These new demands included: That the DMZ be accepted as a true international boundary; that a token withdrawal of North Vietnamese troops take place; that the North Vietnamese guarantee an Indochina-wide cease fire; and that a strong international peace-keeping force (the ICCS) be created for supervising and enforcing the cease-fire.

Once the North Vietnamese read the new demands, they began to retract their own concessions and wanted to bargain anew, leading Kissinger to proclaim that they were "stalling." The talks, scheduled to last ten days, ended on 13 December with both parties agreeing to resume negotiations. Teams of experts from each side met to discuss technicalities and protocols on 14 December, during which the North Vietnamese representatives submitted a Vietnamese-language text of the protocol on prisoners containing several important changes that Hanoi had failed to gain in the main negotiating sessions. At a subsequent meeting of experts on 16 December, the North Vietnamese side "stone-walled from beginning to end." The talks broke down that day, and the Hanoi negotiators refused to set a date for the resumption of negotiations.

Decisions
Nixon was now working against a January deadline. Kissinger's "peace is at hand" statement had raised expectations of a settlement among the US population. Even weightier on the president's mind was the fact that the new Ninety-third Congress would go into session on 3 January, and the president feared that the heavily Democratic legislative branch would preempt his pledge of "peace with honor" by legislating an end to the war.

Also prompting the president toward some form of rapid offensive action was the cost of the force mobilization that had accompanied Operation Linebacker. The additional aircraft and personnel assigned to Southeast Asia for the operation was straining the Pentagon's budget. The cost of maintaining this "augmentation force" totaled over $4 billion by mid-autumn and Secretary of Defense Melvin Laird insisted that the president request a supplementary defense appropriation from Congress to pay for it. Nixon and Kissinger were convinced that the legislative branch "would seize the opportunity to simply write the United States out of the war."

After returning from Paris on 14 December, and after consultations with Nixon, Kissinger fired off an ultimatum to Hanoi, threatening "grave consequences" if North Vietnam did not return to the negotiating table within 72 hours. On that day, Nixon ordered the reseeding of North Vietnamese ports with air-dropped naval mines and that the Joint Chiefs of Staff direct the Air Force to begin planning for a bombing campaign (a three-day "maximum effort") which was to begin within 72 hours. Two days after the 16 December deadline had passed, the U.S. bombed Hanoi. Senior Air Force officers James R. Mccarthy and George B. Allison stated years later that the operation had been mainly politically driven, as a negotiation tool to "bring the point home".

Many historians of the Vietnam War follow the lead of President Nixon, who claimed that Hanoi's representatives had walked out of the talks, refusing to continue the negotiations. Both sides had proclaimed their willingness to continue the talks; however, Hanoi's negotiators refused to set a date, preferring to wait for the incoming Congress. The goal of President Nixon was not to convince Hanoi, but to convince Saigon. President Thieu had to be convinced that "whatever the formal wording of the cease-fire agreement, he could count on Nixon to come to the defense of South Vietnam if the North broke the cease-fire."

Planning
In the wake of Operation Linebacker, the U.S. had a force of 207 B-52 bombers available for use in Southeast Asia. 54 bombers (all B-52Ds) were based at U-Tapao RTAFB, Thailand, while 153 were based at Andersen Air Force Base, Guam (55 B-52Ds and 98 B-52Gs). This deployment, however, utilized nearly half of the Air Force's manned bomber fleet and Strategic Air Command (SAC) commanders were initially reluctant to risk the highly expensive aircraft and their highly trained crews in such an operation; in addition the production line for B-52s had long since been shut down, and losses could not be replaced. The use of large numbers of B-52s was unprecedented in the war and the proposed large-scale attacks on targets within 10 nmi of Hanoi "represented a dynamic change in the employment of air resources." Many within SAC, however, welcomed the opportunity to fly into the heavily defended airspace of North Vietnam, hoping to finally prove the viability of manned bombers in a sophisticated Soviet-style air defense network of surface-to-air missiles (SAMs), anti-aircraft artillery and MiG interceptors.

One purely local reason for utilizing the B-52s instead of tactical aircraft for the planned campaign was the September through May monsoon weather within North Vietnam, which made visual bombing operations by tactical fighter-bombers difficult. The B-52s were equipped with their own radar bomb navigation systems and supporting fighter-bombers would be able to strike targets with either newly deployed laser-guided bombs in clear weather or by utilizing LORAN and radar-guided bombing systems.

The new operation, given the title Linebacker II, was marked by top-down planning by the SAC headquarters at Offutt AFB, Omaha, Nebraska. Due to the restrictive time frame imposed by Richard Nixon (only three days) and the experience of Linebacker (in which North Vietnamese fighter aircraft had posed the highest threat to the bombers), SAC's plan called for all of the bombers to approach Hanoi at night in three distinct waves, each using identical approach paths and flying at the same altitude. The aircraft themselves were to fly in three-plane formations known as "cells" for more effective electronic warfare (EW) jamming coverage.

Once the aircraft had dropped their bombs, they were to execute what SAC termed "post-target turns" (PTT) to the west. These turns had two unfortunate consequences for the bombers: the B-52s would be turning into a strong headwind, slowing their ground speed by 100 knots (185 km/h) and prolonging their stay in the target area and the PTT would point the emitter antennas of their EW systems away from the radars they were attempting to jam, degrading the effectiveness of the cells, as well as showing the largest radar cross-section to the missile guidance radars. The aircraft employed, however, had significantly different EW capabilities; the B-52G carried fewer jammers and put out appreciably less power than the B-52Ds, however had they had more efficient engines and larger fuel tanks, hence they were assigned to longer range mission routes. Because of these factors, the campaign would ultimately be conducted in three distinct phases as tactics and plans were altered in response to losses to SAMs.

Initial phase
The first three missions of the operation were flown as planned by SAC on three consecutive nights beginning on 18 December. On the first night 129 bombers were launched, 87 of them from Guam. 39 support aircraft of the Seventh Air Force, the Navy's Task Force 77, and the Marine Corps supported the bombers by providing F-4 fighter escorts, F-105 Wild Weasel SAM-suppression missions, Air Force EB-66 and Navy EA-6 radar-jamming aircraft, chaff drops, KC-135 refueling capability, and search and rescue aircraft; the skies were dominated by American airpower to ensure the safety of the aircraft involved in the operation. One B-52 bomber pilot flying out of Guam recalled "We took off one airplane a minute out of Guam for hours. Just on time takeoff after on time takeoff."

The targets of the first wave of bombers were the North Vietnamese airfields at Kep, Phuc Yen, and Hoa Lac and a warehouse complex at Yen Vien while the second and third waves struck targets around Hanoi itself. Three aircraft were shot down by the 68 SAMs launched by North Vietnamese batteries, two B-52G's from Andersen and a B-52D from U-Tapao. Two D models from Andersen with heavy battle damage managed to limp into U-Tapao for repairs. Only one of the three downed crews could be rescued. That same evening, an Air Force F-111 Aardvark was shot down while on a mission to bomb the broadcasting facilities of Radio Hanoi.

Unlike the initiation of Linebacker, which had been launched in response to a North Vietnamese offensive in South Vietnam, President Nixon did not address the nation on television to explain the escalation. Instead, Kissinger held a press conference at which he accused (at Nixon's behest) Le Duc Tho of having "backed off" on some of the October understandings.

On the second night, 93 sorties were flown by the bombers. Their targets included the Kinh No Railroad and storage area, the Thai Nguyen thermal power plant, and the Yen Vien complex. Although 20 SAMs were launched and a number of the bombers were damaged, none were lost on the mission. SAC expected that the third (and supposedly last) night of the operation would proceed just as well as the previous one.

The targets of the 99 bombers sent in on 20 December included the Yen Vien Railroad yards, the Ai Mo warehouse complex, the Thai Nguyen power plant, a transhipment point at Bac Giang, the Kinh No Railroad complex, and the Hanoi petroleum products storage area–all in or near Hanoi. The combination of repetitive tactics, degraded EW systems, and limited jamming capability, however, led to dire consequences when, as the official Air Force history of the campaign has stated, "all hell broke loose."

The repetitious nature of the previous evening's strike profiles had allowed North Vietnamese air defense forces to anticipate strike patterns and to salvo 34 missiles into the target area. Four B-52Gs and three B-52Ds were lost in the first and third waves of the mission. A fourth D model, returning to Thailand, crashed in Laos. Only two of the eight downed crews were recovered by search and rescue aircraft.

The repercussions from the mission were fast and furious. SAC headquarters was under pressure from "many external sources" to "stop the carnage...it has become a blood bath." Of more concern was the position taken by many senior Air Force officers "that we would lose too many bombers and that airpower doctrine would be proven fallacious...or, if the bombing were stopped, the same thing would occur."

The main problem seemed to lie within the headquarters of SAC, which had based its tactics on a MiG threat that had not materialized during the three missions. The tactics utilized (flight paths, altitudes, formations, timing, etc.) had not varied. The Air Force explanation for this course of events was that the similarity would be helpful to the B-52 crews, who were inexperienced in flying in such high-threat environments. Air Force historian Earl Tilford offered a differing opinion: "Years of dropping bombs on undefended jungle and the routines of planning for nuclear war had fostered a mind-set within the SAC command that nearly led to disaster...Poor tactics and a good dose of overconfidence combined to make the first few nights of Linebacker nightmarish for the B-52 crews."

Re-evaluation


It was at this point that President Nixon ordered that the effort be extended past its original three-day deadline. The first change that could be made by local Air Force commanders was divulged by a comparison of the differences between the radar jamming equipment of the B-52 models. The equipment aboard the G models was designed for use in the more sophisticated air defense environment of the Soviet Union, not against the more antiquated SAM-2 and FAN-SONG radar systems utilized by the North Vietnamese. SAC headquarters in Omaha stipulated that only the aircraft stationed at U-Tapao (equipped with more powerful and sophisticated ECM gear) be allowed over the North. As a result the attack waves were reduced in size, although the tactics employed did not change.

On the fourth night (21 December) of the operation, 30 of the U-Tapao bombers struck the Hanoi storage area, the Van Dien storage depot, and Quang Te Airfield. Two more of the D models were lost to SAMs. On the following night, the target area shifted away from Hanoi to the port city of Haiphong and its petroleum storage areas. Once again, 30 aircraft participated in the strikes, but this time there were no losses among the bombers. An F-111, however, was shot down over the Kinh No Railroad complex.

On the 22nd, a wing of the Bach Mai Hospital, located in the southern suburbs of Hanoi, was struck by an errant string of bombs from a single B-52. The civilian deaths were turned into a cause celebre by the North Vietnamese and U.S. peace activists. The hospital sat 1 kilometer from the runway of Bach Mai Military Airfield and a major fuel storage facility was only 200 yards away. Fortunately, the patients of the hospital wing had been evacuated from the city, but 28 doctors, nurses, and pharmacists were killed.

Two days before Christmas, SAC added SAM sites and airfields to the target list. Air Force F-111s were sent in before the arrival of the bombers in order to strike the airfields and reduce the threat of enemy fighters. The Aardvarks proved so successful in these operations that their mission for the rest of the campaign was shifted to SAM site suppression.

The bomber missions of the sixth night (23 December) again avoided Hanoi and hit SAM sites northeast of the city and the Lang Dang Railroad yards. There were no losses. On the following night, the run of luck (and avoidance of Hanoi) continued. Thirty bombers, supported by 69 tactical aircraft, struck the railyards at Thai Nguyen and Kep and no American aircraft were lost during the mission.

Although the Stratofortresses garnered the lion's share of the publicity during the campaign, their "little brothers", the tactical aircraft, were also hard at work. While the B-52s and F-111s attacked by night, an average of 69 tactical aircraft of the Air Force, Navy and Marines attacked by day (averaging nearly 100 sorties per day). Losses for these aircraft were extremely light, with fewer than a dozen lost during the entire campaign. It was not difficult for their crews to deduce why. The North Vietnamese air defense forces "simply waited for nightfall and the arrival of more lucrative targets."

Final phase
The strikes of the 24th were followed by a 36-hour Christmas stand-down, during which Air Force planners went to work to revise their plans for the next phase of operations. Due to aircraft losses during the initial phase, they intended to launch an all-out attack on North Vietnam's air defenses when the operation resumed. This course was also necessary since, by Christmas, most of the strategic targets within North Vietnam were in shambles.

SAC also belatedly turned over tactical mission planning to its subordinate Eighth Air Force headquarters on Guam, which promptly revised the previously costly tactics. Instead of utilizing multiple waves, all of the bombers would be in and out of the target area within 20 minutes and they would approach from multiple directions and at different altitudes. They would exit by varying routes and the steep PTTs were eliminated. Ten targets, in both the Hanoi and Haiphong areas, were to be struck by bombers approaching in seven separate streams, four of which were to come in off the Gulf of Tonkin. Additional jammers were also installed in the B-52Gs, allowing them to return to the operation.

On 26 December 120 bombers lifted off to strike Thai Nguyen, the Kinh No complex, the Duc Noi, Hanoi, and Haiphong Railroads, and a vehicle storage area at Van Dien. 78 of the bombers took off from Andersen in one time block, the largest single combat launch in SAC history, while 42 others came in from Thailand. The bombers were supported by 113 tactical aircraft which provided chaff corridors, escort fighters, Wild Weasel SAM suppression, and electronic countermeasures support.

The North Vietnamese air defense system, though still capable, was overwhelmed by the number of aircraft it had to track in such a short time period and by a dense blanket of chaff laid down by the fighter-bombers. 250 SAMs had been fired, and the strain on the remaining North Vietnamese inventory showed, since only 68 were fired during the mission. One B-52 was shot down near Hanoi and another damaged aircraft made it back to U-Tapao, where it crashed just short of the runway. Only two members of the crew survived.

On the following night, 60 bombers flew the mission, with some attacking SAM sites while others struck Lang Dang, Duc Noi, the Trung Quang Railroad, and Van Dien. One B-52 was so heavily damaged that its crew ejected over Laos, where it was rescued. A second aircraft was not so lucky. It took a direct hit and went down while attacking the Trung Quang Railroad yards. During the evening's operations two F-4s and an HH-53 search and rescue helicopter were also shot down.

Day ten (28 December) called for strikes by 60 B-52s–15 Gs and 15 Ds from Andersen and 30 Ds from U-Tapao, The aircraft formed six waves attacking five targets. Four of the waves struck targets in the Hanoi area (including SAM Support Facility #58), while the fifth hit the Lang Dang Railroad yards southwest of Lang Son, a major chokepoint on the supply route from the People's Republic of China. No aircraft were lost on the mission.

By the eleventh and final day (29 December), there were few strategic targets worthy of mention left within North Vietnam. There were, however, two SAM storage areas at Phuc Yen and the Lang Dang yards that could be profitably attacked. A total of 60 aircraft again made the trip north, but the mix was altered; U-Tapao again provided 30 D models but the Andersen force was varied, putting 12 G models and 18 Ds over the north. Total bombing was rounded out by sending 30 G models on Arclight missions in southern panhandle of North Vietnam and in South Vietnam. Once again, there were no aircraft losses to anti-aircraft fire, MiGs, or missiles.

Negotiating
On 22 December, Washington asked Hanoi to return to the talks with the terms offered in October. On 26 December, Hanoi notified Washington that it was willing to "impress upon Nixon that the bombing was not the reason for this decision, the VWP Politburo told Nixon that halting the bombing was not a precondition for further talks." Nixon replied that he wanted the technical discussions to resume on 2 January and that he would halt the bombing if Hanoi agreed. They did so and Nixon suspended aerial operations north of the 20th parallel on 29 December. He then informed Kissinger to accept the terms offered in October, if that was what it took to get the agreement signed. Senator Henry Jackson (D, Wash.), tried to persuade Nixon to make a televised address in order to explain to the American people that "we bombed them in order to get them back to the table." It would, however, have been extremely difficult to get informed observers in the U.S. to believe that he "had bombed Hanoi in order to force North Vietnamese acceptance of terms they had already agreed to."

Now the only stumbling block on the road to an agreement was President Thieu. Nixon tried to placate him by writing on 5 January that "you have my assurance of continued assistance in the post-settlement period and that we will respond with full force should the settlement be violated by North Vietnam." By this time, however, (due to congressional opposition) Nixon was in no position to make such a promise, since the possibility of obtaining the requisite congressional appropriations was nil. The South Vietnamese president, however, still refused to agree. On the 14th Nixon made his most serious threat: "I have therefore irrevocably decided to proceed to initial the agreement on 23 January 1973...I will do so, if necessary, alone. One day before the deadline, Thieu bowed to the inevitable and consented to the agreement.

On 9 January Kissinger and Le Duc Tho returned to Paris. The agreement struck between the U.S. and North Vietnam was basically the same one that had been reached in October. The additional demands that had been made by the U.S. in December were generally discarded or went against the U.S. John Negroponte, one of Kissinger's aides during the negotiations, was more caustic: "We bombed the North Vietnamese into accepting our concessions." The DMZ was defined as provided for in the Geneva Accords of 1954, and would in no way be recognized as an international boundary. The demanded withdrawal of North Vietnamese troops from South Vietnam was not mentioned at all in the text of the agreement. Kissinger did, however, obtain a "verbal agreement" from Tho for a token withdrawal of 30,000 North Vietnamese troops.

The demand for an inclusive, Indochina-wide cease-fire was simply discarded in the written agreement. Once again, Kissinger had to be satisfied with a "verbal understanding" that a cease-fire would be instituted in Laos simultaneous with, or shortly following, that in South Vietnam. An agreement on Cambodia (where the North Vietnamese had no influence whatsoever over the Khmer Rouge) was out of the question. The size of the ICCS was finally decided by splitting the difference in the number demanded by both parties at 1,160 personnel. The Paris Peace Accords were signed at the Majestic Hotel in Paris on 27 January 1973.

Aftermath
During operation Linebacker II a total of 741 B-52 sorties had been dispatched to bomb North Vietnam and 729 had actually completed their missions. 15,237 tons of ordnance were dropped on 18 industrial and 14 military targets (including eight SAM sites) while fighter-bombers added another 5,000 tons of bombs to the tally. 212 additional B-52 missions were flown within South Vietnam in support of ground operations during the same time period. Ten B-52s had been shot down over the North and five others had been damaged and crashed in Laos or Thailand. 33 B-52 crew members were killed or missing in action, another 33 became prisoners of war, and 26 more were rescued. North Vietnamese air defense forces claimed that 34 B-52s and four F-111s had been shot down during the campaign.

769 additional sorties were flown by the Air Force and 505 by the Navy and Marine Corps in support of the bombers. 12 of these aircraft were lost on the missions (two F-111s, three F-4s, two A-7s, two A-6s, an EB-66, an HH-53 rescue helicopter, and an RA-5C reconnaissance aircraft). During these operations, ten American aviators were killed, eight captured, and 11 rescued. Overall US Air Force losses included fifteen B-52s, two F-4s, two F-111s, one EB-66 and one HH-53 search and rescue helicopter. Navy losses included two A-7s, two A-6s, one RA-5, and one F-4. Seventeen of these losses were attributed to SA-2 missiles, three to daytime MiG attacks, three to antiaircraft artillery, and four to unknown causes. A total of eight MiGs were shot down during the operation, including two by B-52 tail gunners.

Damage to North Vietnam's infrastructure was severe. The Air Force estimated 500 rail interdictions had taken place, 372 pieces of rolling stock and three million gallons of petroleum products were destroyed, and 80 percent of North Vietnam's electrical power production capability had been eliminated. Logistical inputs into North Vietnam were assessed by U.S. intelligence at 160,000 tons per month when the operation began. By January 1973, those imports had dropped to 30,000 tons per month. The North Vietnamese government criticized the operation stating that the U.S. had "carpet-bombed hospitals, schools, and residential areas, committing barbarous crimes against our people", citing the bombing of Bach Mai Hospital and Kham Thien street on 26 December which they claimed had resulted in 278 dead and 290 wounded, and over 2,000 homes destroyed. In total, Hanoi claimed that 1,624 civilians had been killed by the bombing.

Both the Soviet Union and China denounced the bombing, while some Western countries also criticized the US operation. In a famous speech, Olof Palme, the Prime Minister of Sweden, compared the bombings to a number of historical "crimes" including the bombing of Guernica, the massacres of Oradour-sur-Glane, Babi Yar, Katyn, Lidice and Sharpeville, and the extermination of Jews and other groups at Treblinka, and said that "now another name can be added to this list: Hanoi, Christmas 1972". His protests resulted in that the U.S. withdraw their ambassador from Sweden and told Sweden to not send a new ambassador to Washington. In America, Nixon was criticized as a "madman", and some of the people who supported Operation Linebacker I, questioned the necessity and unusual intensity of Operation Linbacker II.

The US claimed that the operation had succeeded in forcing DRV's Politburo to return to negotiating, with the Paris Peace Accords was signed shortly after the operation. However the agreement clearly benefited the PAVN. Also, sources indicated that when RVN's President Nguyen Van Thieu objected to the terms, Nixon threatened that he might follow the footsteps of Ngo Dinh Diem (implying that Thieu might also find himself deposed by a military coup). Also, while the bombing did severe infastructure damage in Northern Vietnam, it did not break the stalemate in the South, nor did it halt the endless stream of supplies flowing down the Hochiminh Trail.