Operation Freedom Deal was a United States Seventh Air Force interdiction and close air support campaign waged in Cambodia between 19 May 1970 and 15 August 1973, as an expansion of the Vietnam War, as well as the Cambodian Civil War. Launched by Richard Nixon as a follow-up to the earlier ground invasion during the Cambodian Campaign, the initial targets of the operation were the base areas and border sanctuaries of the People's Army of Vietnam (PAVN) and the Viet Cong (NLF). As time went on most of the bombing was carried out to support the Cambodian government of Lon Nol in its struggle against the communist Khmer Rouge. The area in which the bombing took place was expanded to include most of the eastern one-half of Cambodia.The bombing was extremely controversial, and led the US Congress to pass the War Powers Resolution.
Operation Freedom Deal followed and expanded the bombing of Cambodia conducted under Operation Menu in 1969 and 1970. Most of the bombing was carried out by U.S. Air Force B-52 heavy bombers. While the effectiveness of the bombing and the number of civilians killed by U.S. bombing is in dispute, fatalities were easily in the tens of thousands.
With the end of Cambodian neutrality (due to a coup that ousted Prince Norodom Sihanouk and installed pro-US General Lon Nol as president), the Cambodian civil war escalated as the People's Army of Vietnam (PAVN) reacted to military actions by the Cambodians, Americans, and South Vietnamese.
On 15 March 1970, Lon Nol issued an ultimatum to the North Vietnamese, ordering them out of the border areas. The PAVN and their indigenous Khmer Rouge allies had occupied eastern Cambodia for the previous ten years and had established a logistical system and Base Areas along the border during their struggle for a unified Vietnam. They were not about to abandon their zones of control without a fight.
The newly renamed Khmer Republic (which will herein still be referred to as Cambodia) enlarged and renamed its army Forces Aremees Nationales Khmeres or FANK and launched it against the PAVN. Hanoi's response to the ultimatum and this offensive was the launching of Campaign X in April. PAVN and Viet Cong (NLF) forces easily seized eastern and northern Cambodia, leaving only a few isolated FANK enclaves.
The U.S. responded by first launching Operation Patio, which consisted of tactical airstrikes into Cambodia as an adjunct to the highly classified Operation Menu, the strategic bombardment of the Base Areas by B-52s. The Menu bombing pushed NLF forces deeper into Cambodia, which led to a more expansive U.S. bombing campaign. The U.S. and the Republic of Vietnam (RVN or South Vietnam) then launched offensive ground operations in May 1970 during the Cambodian Campaign.
President Richard M. Nixon, however, had placed a 30 June deadline on the operation, after which all US ground forces had to return to South Vietnam. This did not bode well for the Lon Nol government. Although the incursion had temporarily thrown the PAVN and NLF off balance, they and the Khmer Rouge struck back against FANK forces. As a result of this state of affairs, Freedom Deal, the overt air support afforded to the incursion, was extended on 6 June.
In the post-incursion period, Freedom Deal was originally an interdiction effort, striking enemy supply lines in eastern Cambodia and it was restricted to a 50-kilometer (30 mi) deep area between the South Vietnamese border and the Mekong River. This restriction was, however, quickly voided due to Search and Rescue operations conducted by the U.S. Air Force in order to pick up downed South Vietnamese pilots, who regularly flew outside the Freedom Deal zone. Within two months (and without public announcement), the operation was expanded west of the Mekong.
The withdrawal of U.S. forces in May left only South Vietnamese and Cambodian forces to do battle with PAVN and the Khmer Rouge. U.S. tactical aircraft then began supplying FANK troops with direct air support. Meanwhile, President Nixon had announced that the policy of the U.S. Air Force was only to interdict PAVN/NLF supply networks (in the same manner that they were interdicted in Laos), and that they were only to be conducted within the specified zone (known as the AIZ or Aerial Interdiction Zone).
During the rest of the year, the Freedom Deal area of operations was expanded three times. Transcripts of telephone conversations reveal that by December 1970 Nixon's dissatisfaction with the success of the bombings prompted him to order that they be stepped up. "They have got to go in there and I mean really go in," he told Henry Kissinger. "I want them to hit everything. I want them to use the big planes, the small planes, everything they can that will help out there, and let's start giving them a little shock." The president was inspired to reckless escalation by his belief in the "madman theory." 
By the beginning of 1971, the area of operations stretched from Route 7 to the Laotian border in the north and 120 kilometers (75 mi) beyond the Mekong to the west. Between July 1970 and February 1971, approximately 44 percent of the 8,000 sorties flown in Cambodia struck targets outside the authorized zone. This led to Kissinger, Alexander Haig and Colonel Ray Sitton developing a policy of falsifying the reports of missions carried out beyond the boundary.
Most of the strikes were flown in direct support of FANK troops, although American officials continued to deny the fact. Despite this effort, the communists occupied one-half of Cambodia by late 1970 and had cut all the land routes leading to and from the capital of Phnom Penh. In short order the U.S. Air Force found itself shifting more and more of its diminishing air power from its interdiction campaign in southern Laos to the struggle in Cambodia. In 1971 Cambodian missions made up nearly 15 percent of the total number of combat sorties flown in Southeast Asia, up from eight percent during the previous year.
According to George McTurnan Kahin, Freedom Deal bombers treated the communist-held parts of the country as a virtual "free-fire zone." For most of the campaign, US Ambassador Emory Swank and his team were only allowed to vet targets west of the Mekong. Often they had no idea what villages were being bombed.  Swank soon resigned, one of several foreign policy officials who left because of Kissinger's Cambodia policy.
In Cambodia, the ground war dragged on, with the Khmer Rouge doing the bulk of the fighting against the government. On 28 January 1973, the day the Paris Peace Accord was signed, Lon Nol announced a unilateral cease-fire and U.S. airstrikes were halted. When the Khmer Rouge refused to respond, the bombing resumed on 9 February. The US Seventh Air Force argued that the bombing prevented the fall of Phnom Penh in 1973 by killing 16,000 of 25,000 Khmer Rouge fighters besieging the city. In March the U.S. Joint Chiefs of Staff proposed a much expanded bombing campaign. From then until the end of the operation on 15 August, sortie and tonnage rates increased. By the last day of Operation Freedom Deal (15 August 1973), 250,000 tons of bombs had been dropped on the Khmer Republic, 82,000 tons of which had been released in the last 45 days of the operation.
During 1973 Freedom Deal aircraft dropped 250,000 tons of bombs (primarily high explosive), more than the 180,000 tons dropped on Japan during the Second World War. As communist forces drew a tighter ring around Phnom Penh in April, the U.S. Air Force flew more than 12,000 bombing sorties and dropped more than 82,000 tons of ordnance in support of Lon Nol's forces during the last 45 days of the operation. Since the inception of the Menu bombings in March 1969, the total amount of ordnance dropped on Cambodia reached 539,129 tons. On 15 August, the last mission of Freedom Deal was flown.
Additional detail concerning the disputed effectiveness of the bombing of Cambodia is in the article Operation Menu. According to David Chandler: "If you just made a very cold, calculating, military decision, the bombing of 1973 was in fact a sensible thing to do [at the time], because had it not happened, the Khmer Rouge would have taken Phnom Penh [much earlier] and South Vietnam would have had a communist country on its flank." In contrast, Pulitzer prize-winning correspondent Sidney Schanberg asserted that the campaign actually fostered the Khmer Rouge's growth, recalling that the militia men "would point... at the bombs falling from B-52s as something they had to oppose if they were going to have freedom. And it became a recruiting tool until they grew to a fierce, indefatigable guerrilla army." 
U.S. bombing of Cambodia extended over the entire eastern one-half of the country and was especially intense in the heavily populated southeastern one-quarter of the country, including a wide ring surrounding the largest city of Phnom Penh. In large areas, according to maps of U.S. bombing sites, it appears that nearly every square mile of land was hit by bombs.
When extensive bombing by the U.S. of Cambodia began in 1969 it was primarily directed against the North Vietnamese army and its supply lines and depots. As the North Vietnamese dispersed their operations deeper into Cambodia to escape U.S. bombing the area bombed by the U.S. expanded. Increasingly, U.S. bombing missions had the objective of supporting the government of Cambodia in its war against the insurgent Khmer Rouge.[dead link]
The number of deaths caused by U.S. bombing has been disputed and is difficult to disentangle from the broader Cambodian Civil War. Estimates as wide-ranging as 30,000 to 500,000 have been cited. Sihanouk used a figure of 600,000 civil war deaths, while Elizabeth Becker reported over one million civil war deaths, military and civilian included. Marek Sliwinski notes that many estimates of the dead are open to question and may have been used for propaganda, suggesting that the true number lies between 240,000 and 310,000; Judith Banister and E. Paige Johnson described 275,000 war deaths as "the highest mortality we can justify"; and Patrick Heuveline states that "Subsequent reevaluations of the demographic data situated the death toll for the [civil war] in the order of 300,000 or less." Of these civil war deaths, Sliwinski estimates that approximately 17.1% can be attributed to U.S. bombing, noting that this is far behind the leading causes of death, as the U.S. bombing was concentrated in under-populated border areas. Ben Kiernan attributes 50,000 to 150,000 deaths to the U.S. bombing.
Another impact of the U.S. bombing and the Cambodian civil war was to destroy the homes and livelihood of many people. This was a large contributor to the refugee crisis in Cambodia with two million people—more than 25 percent of the population—displaced from rural areas into the cities, especially Phnom Penh which grew from about 600,000 in 1970 to an estimated population of nearly 2 million by 1975. The Cambodian government estimated that more than 20 percent of the property in the country had been destroyed during the war.
[The bombing] had the effect the Americans wanted—it broke the Communist encirclement of Phnom Penh.
Le bilan humain de cette périod de guerre civile est difficile à établir. Les chiffres avancés ne sont pas irréfutables, et ils peuvent bien avoir été lancés à des fins de propagande ou d'intoxication. Ils oscillent, pour le nombre des morts, entre 600 000 et 700 000, soit entre 7.7 % et 9.6 % de la population du pays selon les évaluations les plus extrêmes. La cause principale de ces pertes serait les bombardements massifs de l'aviation américaine dont le but principal était l'anéantissement des pistes Ho-Chi-Minh et la destruction d'un mythique Q.G. du Viêt-cong. A cet égard, il est intéressant de rappeler que la population de toutes les régions traversées par les pistes Ho-Chi-Minh, régions situées sur la rive gauche du Mékong, ne comptait au total qu'environ 1 165 000 personnes, et que les trois plus grandes provinces longeant la frontiére laotienne et vietnamienne, Stung Treng, Ratanakiri et Mondolkiri, étaient pratiquement inhabitées. L'impact des bombardments américains sur l'état de la population du Cambodge durant les années 1970-1975 ne paraît donc pas aussi évident que certain auteurs le supposent. Nos propres statistiques sur les causes précises des décés ne situent d'ailleurs les victimes des bombardments qu'à la troisiéme place, loin derriére les victimes des armes à feu portatives et des assassinats. ... Pour la période de guerre civile, l'augmentation totale de la mortalité est donc de 7.5% Si l'on considére que la mortalité naturelle frappe chaque anné quelque 132 000 personnes, on pourrait facilement en déduire que la surmortalité due à la guerre se chiffre par un nombre de décés ne dépassant pas 50 000 personnes durant la périod allant de mars 1970 à avril 1975. Toutefois, en tenant compte du fait que la guerre a eu une forte incidence tant sur la dimunution de la mortalité naturelle que sur l'agumentation de la mortalité infantile, on peut estimer la proportion annuelle des victimes elles-mêmes de cette guerre à 0,64% de la population du pays, soit, pour toutes ces années, 240 000 personnes environ.
An estimated 275,000 excess deaths. We have modeled the highest mortality we can justify for the early 1970s.
As best as can now be estimated, over two million Cambodians died during the 1970s because of the political events of the decade, the vast majority of them during the mere four years of the 'Khmer Rouge' regime. ... Subsequent reevaluations of the demographic data situated the death toll for the [civil war] in the order of 300,000 or less.
Published Government Documents