The Shadow War in Cambodia

Nov. 28, 2017

A B-52 amid a sea of munitions bound for targets in Southeast Asia. Photos: USAF

Cambodia in 1969 was neutral in name only. The Geneva Conference on Indochina in 195?4 had declared it to be a nonaligned nation and the official designation was still in effect.

However, Cambodia’s Prince Norodom Sihanouk, believing Hanoi would win the Vietnam War, had broken off relations with the United States in 1965. He permitted the North Vietnamese and the Viet Cong to use staging bases in Cambodia for operations in South Vietnam.

The Cambodian border with South Vietnam ran for 706 miles from the central highlands to the Mekong Delta. Along that stretch were at least 15 sanctuary bases, one of them in the “Parrot’s Beak,” which hooked into Vietnam only 33 miles from Saigon.

In addition, supplies moved unimpeded along the road from “Sihanoukville”—the port of Kompong Som on the Cambodian coast—to the North Vietnamese base camps.

The US command in Vietnam had for some time wanted to eliminate the Cambodian sanctuaries, but President Lyndon B. Johnson, unwilling to commit either to winning the war or getting out, would not permit it. His successor, Richard M. Nixon, was of a different mind.

On March 15, 1969, Nixon authorized the bombing of the Cambodian bases, insisting that it be done in secret. The North Vietnamese and the Cambodians would know as soon as the bombs fell, of course, but Nixon and his national security advisor, Henry Kissinger, hoped to keep it away from Congress and the press.

Between March 1969 and May 1970, B-52 bombers flew 3,875 missions against targets in Cambodia. This was known only to a limited number of Americans in the field and in Washington, D.C.

The North Vietnamese were in no position to complain because they denied being in Cambodia.

Secrecy was maintained by an elaborate scheme euphemistically called “special security and reporting procedures.” Missions were briefed and launched as strikes against targets in South Vietnam but the B-52s were redirected in flight to different targets nearby in Cambodia.

Records of the actual strikes were destroyed. The entries in falsified reports were for the original targets in South Vietnam. Selected officials were kept abreast of actual events through “back-channel” communications.

Operations in Cambodia moved into the open with a major “incursion” by US and South Vietnamese ground forces in 1970, but the secret B-52 missions—dubbed Operation Menu—did not become public knowledge until revealed in the course of dramatic hearings in the Senate in July 1973.

The Sanctuaries

Sihanouk was having doubts about his bargain with the North Vietnamese and the Viet Cong, who brought in more than 300,000 troops, took over several of the northern provinces, and drove out most of the Cambodians.

Mindful of the historic threat of domination from Vietnam, the slippery Sihanouk hedged his bets. In 1968, he all but invited an American attack.

“We don’t want any Vietnamese in Cambodia,” he told a US emissary. “We will be very glad if you solve our problem. We are not opposed to hot pursuit in uninhabited areas. … I want you to force the Viet Cong to leave Cambodia. In unpopulated areas, where there are not Cambodians—in such precise cases, I would shut my eyes.”

Nixon came to office inclined to take action. According to Kissinger, President-elect Nixon sent him a note before the inauguration asking for a report on Cambodia and “what, if anything, we are doing to destroy the buildup there?”

In February 1969, Gen. Creighton W. Abrams at Military Assistance Command Vietnam renewed his request for bombing the Cambodia sanctuaries. US Ambassador Ellsworth Bunker supported the proposal but Secretary of State William P. Rogers and Secretary of Defense Melvin R. Laird had objections.

“They feared the fury of Congress and the media if I expanded the war into Cambodia,” Nixon said in his memoirs. That was not exactly the case. What Laird opposed was the secrecy, not the bombing. “I was all for hitting those targets in Cambodia, but I wanted it public,” Laird said.

As Kissinger told it later, the secrecy was supposed to be temporary. “The original intention had been to acknowledge the first strike when Cambodia or North Vietnam reacted, which we firmly anticipated,” Kissinger said. “But Hanoi did not protest, and Sihanouk not only did not object, he treated the bombing as something that did not concern him because it occurred in areas totally occupied by North Vietnamese troops.”

Nevertheless, the administration went to exceptional lengths over the next three years to keep the operation hidden.

_You can read this story in our print issue:

Secret Orders

The Pentagon sent a Joint Staff officer with deep experience in B-52s to discuss the options with Kissinger, and the outlines of a plan emerged.

Regular “Arc Light” missions, flown by B-52s from Guam against targets in South Vietnam, could be used as cover for strikes in Cambodia. Once they were airborne, the crews could receive new target directions.

The strikes would be controlled from the ground by the Combat Skyspot radar bombing system, which would guide the B-52s across the border to the exact location at which to drop their bombs.

Kissinger suggested the B-52 crews not be informed of their real destinations, but was told that the pilots and navigators, who had their own instruments aboard, would know when they were in Cambodia.

The list of those regarded as having a “need to know” was short. At Nixon’s direction, Kissinger briefed a handful of leaders in Congress. In the Pentagon, only the Secretary of Defense, the Joint Chiefs of Staff, and a few others were in the loop. The Secretary of the Air Force and the Vice Chief of Staff were not told.

At Strategic Air Command, the commander in chief and one operations planner knew, as did a minimum number of people at US Pacific Command and at MACV and 7th Air Force in Saigon.

At Andersen Air Force Base on Guam, the commander of the SAC air division personally briefed B-52 pilots and navigators flying the missions, but others on the crews were not informed. All of the missions would be conducted at night.

A key point in the chain was the Combat Skyspot radar station at Bien Hoa Air Base in Vietnam, manned by SAC personnel but under the operational control of 7th Air Force. In 1969, the supervisor of the radar crews at Bien Hoa was Maj. Hal Knight.

On the afternoon before a mission, a special courier brought the new targets to Knight in a plain manila envelope. His radar crews prepared the computations and computer input tapes and later that night, transmitted the target coordinates to the B-52s.

After the strike, Knight collected and burned every scrap of paper with the actual strike locations. The post-strike report was filled in with the coordinates of the original cover targets in South Vietnam.

As Army Gen. Bruce Palmer Jr., commander of Field Force II in Vietnam, said later in his book, The 25-Year War, this system “placed the military in an impossible position, having literally to lie publicly about a perfectly legitimate wartime operation. It had nothing to do with keeping the operations secret from the enemy, who had to know all about them, nor did the decision have anything to do with enhancing the safety of the combat aircrews making the attack.”


The first strike was March 18, 1969, when 48 B-52s were diverted to the “Fish Hook” area of Cambodia, which juts into Vietnam just above Tay Ninh. The code name for the target was “Breakfast,” an insider’s reference to a key breakfast meeting in the Pentagon in February at which fundamentals of the plan were laid down.

The overall program was called Operation Menu. The targets were six of the sanctuary base areas, labeled “Breakfast,” “Snack,” “Lunch,” “Dinner,” “Supper,” and “Dessert.” Palmer declared the code names to be “tasteless.”

As the Department of Defense explained later, each mission was “flown in such a way that the Menu aircraft on its final run would pass over or near the target in South Vietnam and release its bombs on the enemy in the Menu sanctuary target area.”

What Kissinger described in his memoirs as “the double bookkeeping the Pentagon had devised” was necessary to keep track of logistics data on hours and missions flown, which determined fuel and munitions required and the forecast for the number of spare parts to be ordered.

Security was not airtight. A sketchy article by William M. Beecher in The New York Times May 9 reported that, “American B-52 bombers in recent weeks have raided several Viet Cong and North Vietnamese supply dumps and base camps in Cambodia for the first time, according to Nixon administration sources, but Cambodia has not made any protest.”

At Kissinger’s request, the FBI placed wiretaps on 17 White House and Pentagon officials, but no leakers were caught.


Operations moved into the open May 1, 1970, with an “incursion” into Cambodia by 15,000 US and South Vietnamese ground troops to destroy North Vietnamese and Viet Cong bases.

The incursion was welcomed by the new regime in Cambodia headed by Lon Nol, who had overthrown Sihanouk. He told the North Vietnamese to leave the country, and closed the port of Sihanoukville to them. Sihanouk fled to China and solidified his ties to North Vietnam.

In announcing the incursion on television, Nixon said that, “For the past five years neither the United States nor South Vietnam has moved against these enemy sanctuaries because we did not wish to violate the territory of a neutral nation.”

Operation Menu overlapped with the incursion for a few weeks, then gave way to non-secret strikes by US bombers and fighter-bombers, which continued after the incursion ended in June.

A massive wave of protests against the incursion by politicians, the press, and students followed. In December 1970, the Cooper-Church Amendment to the defense appropriations bill prohibited all use of US ground troops in Laos or Cambodia.

Among those bothered by developing events was Hal Knight, the Combat Skyspot officer from Bien Hoa, who was no longer in the Air Force. His misgivings about the falsified reports led to two bad effectiveness ratings. He was passed over for promotion and resigned.

In December 1972, Knight wrote to Sen. William Proxmire (D-Wis.), a noted critic of the Pentagon, about the secret bombings. Proxmire forwarded the letter to Sen. Harold Hughes (D-Iowa), a member of the Senate Armed Services Committee and a leading opponent of the conduct of the war. Hughes bided his time in making use of the information.

Air operations in Cambodia continued after the cease-fire in Vietnam in January 1973. The administration held that the bombing was necessary to force Hanoi to agree to a parallel cease-fire in Cambodia, as called for in the Vietnam accords.

In March 1973, the Senate Armed Services Committee asked the Department of Defense for records of air operations in Cambodia. The ensuing report did not mention any B-52 attacks before May 1970.


In the summer of 1973, the Senate challenge to air strikes in Cambodia reached the boiling point. Nixon, weakened by the expanding Watergate scandal and faced with a cutoff of funds by Congress, agreed June 30 to end the bombing of Cambodia by Aug. 15 unless he got congressional approval.

On July 12, Gen. George S. Brown—who in 1969 had been commander of 7th Air Force—came before the Senate Armed Services Committee for confirmation as USAF Chief of Staff.

Senator Hughes asked him if there had been air strikes in Cambodia prior to May 1970. Brown immediately asked the committee to go into executive session, where he said the bombing had indeed taken place.

Knight was called to testify. On July 16, Secretary of Defense James R. Schlesinger acknowledged that B-52s had secretly bombed Cambodia in 1969 and 1970. The Pentagon said “the destruction of documents and other procedures outlined by Mr. Knight had been authorized at higher levels.”

Laird, by then out of office, said that he had approved “a separate reporting procedure” but that he “did not authorize any falsification of records” and had not known about the burning of files or reports.

Kissinger told The New York Times that the White House had “neither ordered nor was aware of any falsification of records,” which he thought was “deplorable.”

Gen. Earle G. Wheeler, who had been Chairman of the Joint Chiefs of Staff during the Menu bombing, said that Nixon personally demanded the tightest security measures possible for the operation.

The military had devised the mechanics of the dual-reporting system, Wheeler said, but there was no “intent to deceive,” which would be the basis for any charge of falsification under military law. Key individuals in the chain of command knew the truth about what was going on.

A Pentagon report to Congress in August laid out the facts and figures of the operation and said that, “everyone in the reporting chain received and reported that information for which he had a need to know. Those who had no need to know about Menu could not perceive a difference between Menu and any other sorties.”

Final Curtain(s)

B-52s and other US aircraft flew missions in Cambodia up to the Aug. 15 deadline. Their efforts are generally credited with strengthening the position of the Lon Nol government and buying it a little more time.

The House Judiciary Committee in July 1974 declined to include the falsification of records in its proposed articles of impeachment against Nixon, despite some clamor that it do so.

Concurrent with the North Vietnamese invasion and the fall of South Vietnam in 1975, the Communist Khmer Rouge insurgents captured Phnom Penh, overthrew Lon Nol, and changed the name of the country to Kampuchea. Between two and three million Cambodians died in the reign of terror that followed.

Sihanouk came back along with the Khmer Rouge, who made him titular president, then put him under house arrest after a falling out. He was rescued when Vietnam ousted the Khmer Rouge in 1979. Even so, he defended the Khmer Rouge in remarks at the United Nations, saying the country’s real enemy was Vietnam.

In 1993, Sihanouk was restored as king, a title he had abdicated in 1955 in a ploy to gain greater political advantage as prime minister. He retained a figurehead monarchy for the rest of his life but no longer exercised any real power. Since 1997, the country has been in the firm control of the Cambodia People’s Party, which evolved from the Khmer Rouge.

_John Correll was Editor in Chief of Air Force Magazine for 18 years and is now a contributor. His most recent article, “The Neutron Bomb,” appeared in the December 2017 issue.