Operation Barrel Roll Operation " Barrel Roll " was a covert U . S . Air Force 2nd Air Division ( later the Seventh Air Force ) and U . S . Navy Task Force 77 , interdiction and close air support campaign conducted in the Kingdom of Laos between 14 December 1964 and 29 March 1973 concurrent with the Vietnam War . The original purpose of the operation was to serve as a signal to the Democratic Republic of Vietnam ( North Vietnam ) to cease its support for the insurgency then taking place in the Republic of Vietnam ( South Vietnam ) . This action was taken within Laos due to the location of North Vietnam ' s expanding logistical corridor known as the Ho Chi Minh Trail ( the Truong Son Road to the North Vietnamese ) , which ran from southwestern North Vietnam , through southeastern Laos , and into South Vietnam . The campaign then centered on the interdiction of that logistical system . Beginning during the same time frame ( and expanding throughout the conflict ) the operation became increasingly involved in providing close air support missions for Royal Lao Armed Forces , CIA - backed tribal mercenaries , and Thai " volunteers " in a covert ground war in northern and northeastern Laos . " Barrel Roll " and the " Secret Army " attempted to stem an increasing tide of People ' s Army of Vietnam ( PAVN ) and Pathet Lao offensives . " Barrel Roll " was one of the most closely held secrets and one of the most unknown components of the American military commitment in Southeast Asia . Due to the ostensible neutrality of Laos , guaranteed by the Geneva Conference of 1954 and 1962 , both the U . S . and North Vietnam strove to maintain the secrecy of their operations and only slowly escalated military actions there . As much as both parties would have liked to have publicized their enemy ' s own alleged violation of the accords , both had more to gain by keeping their own roles quiet . Regardless , by the end of the conflict in 1973 , Laos emerged from nine years of war just as devastated as any of the other Asian participants in the Vietnam War . Preliminaries ( 1962 – 1964 ) . Background . After a series of political and military machinations conducted by the U . S . , the Pathet Lao , and the North Vietnamese in Laos that are described in the History of Laos since 1945 , a Declaration on the Neutrality of Laos was signed in Geneva , Switzerland on 23 July 1962 . The agreement , an attempt to end a civil war between the Communist - dominated ( and Hanoi - directed ) Pathet Lao , neutralists , and American - backed rightists , included provisions that required the removal of all foreign military forces and precluded the use of Lao territory for interfering in the internal affairs of another country – a blatant effort to shut down North Vietnam ' s growing logistical corridor through southeastern Laos that would become known as the Ho Chi Minh Trail . A coalition Government of National Union was installed in the capital of Vientiane , but it soon ran into difficulties . By the 2 October 1962 deadline for the removal of foreign troops , the North Vietnamese had pulled out only 40 personnel , leaving approximately 6 , 000 troops in the eastern half of the country . Meanwhile , rightist elements ( in control of the army ) opposed the new government . The U . S . played its part by increasing its assistance to the right by covertly supplying the army through Thailand . Despite another international accord , Laos remained ensnared by the political and territorial ambitions of communist neighbors , the security concerns of Thailand and the United States , and geographic fate . Fighting soon erupted between elements of the Pathet Lao and the Royal Lao Army . Although tentative negotiations resumed between the factions , matters took a turn for the worse when neutralist Prime Minister Prince Souvanna Phouma was arrested during a right - wing coup attempt . U . S . Ambassador Leonard Unger then notified the generals that the U . S . government would continue to support Souvanna . This turn of events had a profound effect on Laotian politics : First , it affirmed American support for Souvannah , only a few years after the U . S . had denounced him as a tool of the leftists ; It also caused the neutralists to shift political allies from the left to the right ; Finally , in May 1964 , Souvannah announced the political union of the rightists and neutralists against the left . Heavy fighting broke out on the Plain of Jars as the members of each political grouping chose sides . Souvanna called upon the U . S . for support and was answered in the affirmative by President Lyndon B . Johnson , who was eager to support a rightist / neutralist alliance in Laos . In November 1963 General Maxwell D . Taylor , chairman of the Joint Chiefs of Staff had proposed that U . S . armed reconnaissance missions be conducted over Laos as part of a two phase program that would warn Hanoi of U . S . determination to support the Saigon government . The missions were to take place along North Vietnamese infiltration routes then developing in the Laotian panhandle . On 19 May 1964 low - level photo reconnaissance flights ( codenamed " Yankee Team " ) over southern Laos were authorized and launched by RF - 101 Voodoo aircraft . When they were fired upon during a mission , escort aircraft were provided . Two days later American aircraft began flying low - level photo recon missions over the northern part of the country . The American aerial commitment to the covert war had begun . Covert war . For the Americans , Laos became almost exclusively an air war , one which saw a reversal of the role it played in the conflict in neighboring South Vietnam . In Laos , the Air Force applied conventional air power in the support of an unconventional ground war . The mission of the U . S . Air Force was to seal off the southern Mekong River Valley , thus providing a buffer for Thailand ; insulating the Vientiane government from direct communist threat ; draining PAVN manpower and resources ; and interdiction of the approaches to the Ho Chi Minh trail . For U . S . interests , the aerial interdiction effort against the trail and the protection of Thailand were preeminent and they became the raison d ' être for the covert war in the northeast . According to U . S . Secretary of State Dean Rusk , after 1964 and the increasing U . S . commitment to South Vietnam , " Laos was only the wart on the hog . " Originally , the American arrangement in Laos was based on the premise that the situation in South Vietnam would be controlled within a year or two . A holding action in Laos was all that was thought necessary . No one expected that the conflict would last ten years . Air Force historian Colonel Perry F . Lamy described Washington ' s view of the situation succinctly : Since the fate of Laos did not depend on a military solution in the air or on the ground in Laos and could only be decided by the outcome in Vietnam , winning the war against the DRV in northern Laos was not the objective . Instead , maintaining access to the country was paramount and keeping the Royal Lao government in power became the primary objective . For Hanoi , Laos was also a " limited war " with goals and objectives that were tied to its continued use of the Ho Chi Minh trail . The covert nature of the North Vietnamese logistical effort through Laos also had to be maintained in order to support the fiction that the conflict in South Vietnam was a popular uprising that was not directed by the north . Although PAVN could have fielded enough troops to conquer Laos at any point during the conflict , the communists only sought to instigate a stalemate , one that would allow the trail system to operate unhindered by the Americans and Laotians . Back in 1959 a Laotian Lieutenant Colonel of the minority Hmong tribe had been taken under the wing of the CIA effort in Laos . The highland Hmong were more aggressive than the lowland Lao and Vang Pao was quickly elevated to their leadership in hopes of creating a paramilitary force that would counter the Pathet Lao in the northeast . During 1961 , the first weapons were delivered to the Hmong and their training was begun . Nine CIA specialists , nine U . S . Army Special Forces personnel , and 99 Thai members of the Police Aerial Reconnaissance Unit ( PARU ) participated in the training and equipping of what became known as the " Armée Clandestine " or the secret army . The neutralization agreement forced the abandonment of the Hmong program , but that was not going to last long . Due to North Vietnamese violations of the agreement , President John F . Kennedy authorized a return to covert activities in 1963 . The previous year the CIA and the Thai military had established " Headquarters 333 " at Udon Thani , which acted as a joint U . S . / Thai command center for covert military and intelligence collection activities in Laos . By the end of 1963 , the numbers of the Hmong army had grown to 10 , 000 . To supply the Hmong and Royal Lao armies with more firepower , the Thai government covertly dispatched artillery units to northeastern Laos . Logistical airlift for the covert effort was provided by Air America , Bird and Son , and Continental Air Services , all of which were CIA proprietary airlines . The next stage of the military evolution took place during mid - March 1964 , when the CIA began Project " Water Pump " , a program to train Laotian , Thai , Hmong , and Air America aircrews in flight and maintenance of U . S . - supplied AT - 28 Trojan ground - attack aircraft . This training was conducted by Detachment 6 , 1st Air Commando Wing personnel at Udon Royal Thai Air Force Base , Thailand . The first mission in support of Vang Pao ' s forces took place on 25 May . Eventually , the Royal Laotian Air Force would consist of five wings of ten aircraft each . " Water Pump " could never produce enough pilots , however , since graduation rates barely exceeded the death rate of graduates , who simply flew until they died . The American " civilian pilots " program was phased out in 1966 and " Detachment 6 " ( which continued its training program ) was absorbed by the 606th Air Commando Squadron in the same year . The air program did , however , create the world ' s only guerrilla army with air superiority . Field Marshal . According to President Kennedy ' s " Country Team " directive of 29 May 1961 , all U . S . government agencies operating in a foreign nation were to be placed under the direct supervision of the ambassador . Within Laos that meant the U . S . military was under civilian control , since according to the neutralization agreement , there could never be a senior U . S . military commander within the country . The covert war was , therefore , going to be planned and directed by a civilian within the walls of the embassy . The American official most associated with the conflict in Laos was Ambassador William H . Sullivan , who served from December 1964 until June 1969 . He was also one of the most controversial . Considered brilliant by most and tyrannical by many , Sullivan was despised by the American high command ( both Army and Air Force ) in Saigon , Sullivan ' s demand that he alone maintain complete control over every aspect of American military operations in Laos and the stringent restrictions that he imposed upon those operations , earned him few friends among the military . Few of his detractors , however , considered the difficulties of the ambassador ' s position . He had to balance the competing interests of the CIA , the Seventh Air Force , MACV , and the Thais , and this had to be done without alienating Souvanna Phouma , an ally in all but name who acquiesced to almost every U . S . action within his country , short of outright invasion . The most senior military officer in - country was the AIRA , the ambassador ' s air attaché , an Air Force colonel . The air attaché office originally consisted of that officer and six other personnel . The burgeoning air programs in Laos however , dictated the dispatch of 117 more Air Force personnel during 1966 . The Air Force conducted its operations under the aegis of " Project 404 " , whose mission was to support the Royal Laotian military , the clandestine Hmong army , and to support project personnel , who coordinated the operational end of covert activities in Laos . Eventually , five air operations centers were created in Laos – at Vientiane , Pakse , Savannakhet , Long Tieng , and Luang Prabang . These centers supported the ambassador with intelligence , administrative services , and communications as well as the actual air operations under a program called " Palace Dog " . After the initiation of Operation Rolling Thunder , the sustained aerial campaign against North Vietnam that had begun on 5 March 1965 , the " Barrel Roll " area of operations was divided on 3 April . " Barrel Roll " was to continue in the northeast while the southern portion of the area , where interdiction missions against the Ho Chi Minh trail were paramount , was redesignated " Tiger Hound " . Command and control of that area was handed over to the American commander in Saigon , General William C . Westmoreland . At a 29 March 1965 Southeast Asia Coordinating Committee meeting at Udon Thani , Thailand attended by Ambassador Sullivan , representatives from the 2nd Air Division , MACV , and Air America , responsibilities within the " Barrel Roll " operational area were ironed out . Command and control of the air program would remain in the ambassador ' s hands . Operational control of U . S . air assets devolved from the commander - in - chief , Pacific Forces ( CINCPAC ) in Honolulu through his air deputy at Pacific Air Forces or PACAF , to the 2nd Air Division ( after 1 April 1966 , the Seventh Air Force ) . Targets could be requested by the Royal Lao government , the CIA , or by MACV . Northern Laos , however , was not going to be a priority for the Americans . It was decided at the Honolulu Executive Conference of April 1965 that U . S . aircraft could be used for interdiction in Laos only after close air support needs were met in South Vietnam . General Westmoreland was also granted veto power over bombing , interdiction , and reconnaissance programs outside territorial South Vietnam . That decision placed " Barrel Roll " behind South Vietnam , " Rolling Thunder " , and " Steel Tiger " in order of precedence . Only an estimated two percent of the total U . S . aerial effort in Southeast Asia was going to be utilized in northern Laos . On the offensive ( 1964 – 1970 ) . " Barrel Roll " begins . On 12 December 1964 , " Barrel Roll " was approved by Souvanna Phouma . The program originally consisted of only two U . S bombing sortie s per week that were to be conducted by no more than four aircraft in each strike . Due to the nature of the American agreement with the Thai government ( most U . S . strike aircraft flew from bases in Thailand ) , the aircraft had to first fly to South Vietnam , land , and then take off again for Laos . By 24 December , six armed reconnaissance missions were being conducted per day , but the hoped for reaction from Hanoi did not materialize . The aircraft utilized to support the covert war were an odd assortment of vintage propeller - driven attack aircraft , high performance jet fighter - bomber s , and World War II - era cargo airplanes . This hodgepodge of an air force with its peculiar mix of aircraft and aircrew s flew for eight years in the crowded skies over Laos . The majority of the close air support missions flown in the northeast were conducted by Douglas A - 1 Skyraider s and AT - 28 Trojan s . These propeller - driven ( and Korean War - era ) aircraft came into their own in Southeast Asia , where their heavy ordnance loads , long loiter times , and high maneuverability at low altitudes made them more effective than the " fast movers " of the more modern jet Air Force . Before neutralization , one of the first American activities in support of the Hmong had been the establishment of Lima Sites – air strips on peaks surrounding the strategic Plain of Jars ; during the early 1960s their number had grown to 200 . The Plain of Jars , the cockpit of military actions between the Hmong forces , PAVN , and the Pathet Lao , was a plateau north and northeast of Vientiane wide , covered with grass and small hills spread over an area of approximately . The large stone jars ( some of which weighed between 4 , 000 and 6 , 000 pounds ) that gave the plain its name were thought to be the funeral urns of an earlier culture , although archeologists could not agree upon which one . It quickly became evident that the cyclical pattern of the monsoon weather would dictate the timing and pace of military operations in the northeast . From November through May ( the dry season ) , North Vietnamese and Pathet Lao forces advanced out of Sam Neua Province along Route 6 and out of the Barthelemy Pass through Ban Ban toward the Plain of Jars . The lack of roads and the primitive state of those that did exist forced the communists to stretch their lines of communication taut , inviting counterattack . This Vang Pao ' s forces did from June through October ( the wet season ) , utilizing air power , air mobility , and guerrilla tactics to push the communists back to their starting places . Continuous U . S . air support for " Barrel Roll " operations was provided by the aircraft of the 602nd and 606th Special Operations Squadrons , elements of the 56th Air Commando Wing ( as of 8 April 1967 the 56th Special Operations Wing ) , based at Nakhon Phanom Royal Thai Air Force Base , Thailand . On 25 October 1967 , they were joined by the 22nd Special Operations Squadron . Pre - planned airstrikes in the " Barrel Roll " area were rare . Until 1968 , most U . S . jet fighter - bomber sorties only occurred when aircraft were returning to Thailand from " Rolling Thunder " missions carrying unexpended ordnance loads . They would then be directed to targets in northeastern Laos . Electronic tactical air navigation ( TACAN ) became an absolute necessity in Laos , where mountain peaks and unexpected inclement weather made flying extremely hazardous , especially for older aircraft . This problem was solved by establishing unmanned Air Force stations that broadcast continuous radio transmissions , allowing aerial navigation from fixed geographic reference points . The Air Force also emplaced TSQ - 81 radar sites in the north and northeast to direct " Rolling Thunder " missions over North Vietnam . Rules of engagement . During the entire covert war in Laos there was little love lost between the Air Force commanders at Udon Thani and Saigon and the embassy in Vientiane . Richard Secord , then an Air Force captain serving as liaison between the CIA and the Seventh Air Force , complained that We were always trying to pry assets out of the Air Force at times and places they didn ' t want to go . You had to push ' em , cajole ' em , at times threaten them . . . My people were always trying to corrupt the process because the process itself simply was not structured for our kind of war . . . It was a continual frustration . Secord ' s criticism may have been a little extreme . The Department of Defense had created the 7th / 13 Air Force at Udon in November 1965 for the express purpose of conducting the air war in Laos . According to historian Timothy Castle , Sullivan relegated the Air Force commander and his staff " to the status of clerks hired to carry out his airpower decisions . " The unconventional arrangement bred frustration and the 7th / 13th constantly harped about the use of its air assets in northern Laos . There was constant criticism over the use of air power " serving targets " or utilizing modern fighter - bombers as " long - range artillery . " It was very difficult for the Air Force to grasp that a guerrilla force did not fight like a conventional army . The aerial rules of engagement applied in Laos ( which prescribed the offensive action of pilots and the locations and circumstances under which offensive actions could be taken ) were created to protect the civilian population of the country . To the American pilots that conducted the missions , however , they became complex to the point of incomprehensibility . The rules were constantly altered and elaborated upon by the political decision makers in Washington and Vientiane and bore little relation to the reality on the ground . There were different rules for every type of activity , for each different branch of service , and in each military region . Examples from the early days of aerial operations stipulated that there would be no use of napalm in Laos , that no PAVN trucks could be struck more than 200 meters from a road , and that no enemy forces could be bombed within 1 , 000 meters of a pagoda . Although these restrictions were later altered , there were always others to take their place . There were " no bomb zones " that granted sanctuaries to PAVN and Pathet Lao forces . Pagoda s and suspected PAVN hospitals ( which were unmarked ) were simply turned into ammunition dumps , supply caches , and anti - aircraft sites by an enemy that intently studied American actions and adjusted to them . Butterflies and Ravens . One of the key problems for the early phase of the U . S . air program in Laos was the lack of forward air control ( FAC ) that would have pinpointed ground targets in the rugged , jungle - covered terrain for strike aircraft . The Air Force had no such aircraft in Laos , or anywhere else , having phased out its own programs after the Korean War . In 1963 the Air Force dispatched four " sheep - dipped " Air Commandos of the Combat Control Teams to Laos to work with the CIA . Combat Control Teams consisted of personnel who parachuted into a forward zone and provided air control for the aerial delivery of another unit ( usually paratroops ) . The Air Commandos , who were pragmatic sergeants , discovered the problem , obtained outdated manuals on forward air control and went to work to resolve the issue . In short order , they utilized Air America aircraft and began marking ground targets with smoke rockets . The expedient worked and the program , titled Project " Butterfly " , succeeded brilliantly . The program continued for three years ( until 1966 ) without any questions being raised by higher headquarters . It was not until a visit by General William Momyer , commander of the Seventh Air Force , that the unconventional nature of the program became a problem . Discovering that the Butterflies were neither officers nor pilots , Momyer was incensed and ordered that " that will cease . " The program that replaced the Butterflies ( and which became an even more " sensitive " issue with Momyer ) would contain some of the most colorful personnel of the covert war – the Raven FACs . The Ravens were volunteer Air Force officers who already had 500 flying hours ( six months ) as FACs in South Vietnam and who would serve six - month tours in Laos . There were always going to be shortages of both personnel and aircraft in the new program . Only six Ravens were assigned between 1966 and 1968 to control the ever - expanding amounts of U . S . airpower being utilized in Laos . Even at the height of the program , when they would control one - third to two - thirds of the tactical air strikes in the " Barrel Roll " area , there were never more than 22 Ravens . The Ravens flew the entire gamut of U . S . observation aircraft , from O - 1 Bird Dog s , and U - 17 s , to T - 28s and , eventually more modern O - 2 Skymaster s and OV - 10 Bronco s . Each Raven carried aloft a Laotian observer , who could provide almost immediate clearance for air strike s . On the ground , Laotian Forward Air Guides ( FAGs ) also called in for air support missions and one can only imagine the communications problems that existed between the FAGs ( who spoke minimal English at best ) and American pilots . See - saw war . From 1965 through 1968 , the war in the northeast followed the monsoon cycle , with dry season communist offensives followed by wet season Hmong ( and later Thai ) counteroffensives . Each year the conflict slowly escalated . PAVN would introduce more ( and better equipped ) units and the U . S . would counter by the application of more airpower , producing a strategic stalemate . In July 1966 , PAVN and Pathet Lao forces consisting of three infantry regiments , one independent infantry battalion , and an artillery battalion , seized the town of Nam Bac and then established a defensive line north of Luang Prabang . The communist advance , however , was gradually eroded due to the destruction of its supplies by air power . Vang Pao ' s forces counterattacked in August , driving the enemy back to within of the North Vietnamese border . More communist forces then entered the battle , forcing the Hmong back . The communists moved out to take the Plain of Jars again in 1967 . Laotian victories were few and far between and by the end of the year the situation had become critical , even with the support provided by the American and Laotian Air Forces . PAVN , having a complete understanding of the American military system , began to attack TACAN facilities . U . S . intelligence indicated that between December 1967 and August 1968 , the combined strength of North Vietnamese and Pathet Lao forces increased from about 51 , 000 to over 110 , 000 . The PAVN contingent comprised an estimated 34 , 000 combat troops , 6 , 000 advisors , and 18 , 000 support troops . On 6 December Lima Site 44 was overrun and on the 25th PAVN forces captured Lima Site 61 , the site of a mobile facility . All of these attacks were part of a coordinated effort to reduce the ability of the Americans to strike the communist logistical system during the Tet Offensive . In coordination with Tet , PAVN and the Pathet Lao launched a series of coordinated offensives in northern and southern Laos during 1968 . The dry season offensive in northern Laos began with the communists again seizing the Nam Bac region of Military Region 1 . This they adroitly managed , killing 200 Royal Army troops and capturing 2 , 400 more by 13 January . The offensive ground forward , slowly seizing more territory in the north . In the panhandle , the Laotian garrison at Ban Houi Sane , along Route 9 and west of the U . S . Marines ' Khe Sanh Combat Base , was overrun by " 24th Regiment " of the " 314th PAVN Division " supported by Soviet - built PT - 76 tanks . Further south , PAVN " Group 565 " advanced in Khammouane Province , seizing the rice harvest and placing themselves in position to overrun the cities of Saravane and Attopeu with little forewarning . The offensive then wound down and PAVN forces in southern Laos reorganized . On 12 January , one of the most unusual aerial battles of the Vietnam War took place . Two Soviet - built An - 2 Colt biplanes of the North Vietnamese Air Force attacked Lima Site 85 atop a craggy peak known as Phou Phathi . An Air America Bell 205 helicopter , which had taken off to avoid air - dropped 120mm mortar rounds , then began chasing one of the Colts which had already been struck by ground fire . The aircraft crashed while making evasive maneuvers . The Bell then went after the other Colt , and the helicopter ' s crew chief fired an AK - 47 through a sliding window , shooting the biplane down . The communists were not through with Phou Phathi . The combined TACAN / TSQ - 81 site was , by January , controlling 55 percent of " Rolling Thunder " strikes in northern North Vietnam and 20 percent of the strikes in the " Barrel Roll " area . On 11 March , Lima Site 85 was struck by an attack spearheaded by the sapper s of the " 41st Dac Cong Battalion " and supported by the " 923rd PAVN Infantry Battalion " and the site was quickly overrun . Five of the Air Force technicians manning the site managed to escape , but 11 more were never heard from again and were carried as missing in action . To replace Lima Site 85 , Vang Pao moved against Moung Son and Nakhang , where a new site was erected in July . During July and August , the Hmong forces were assisted by 742 U . S . airstrikes , while another 450 others were conducted throughout the " Barrel Roll " area . 1968 had proved to be a turning point in the conflict , with North Vietnamese forces displaying unprecedented determination in maintaining pressure against Royal forces , regardless of the weather cycles . To preempt the traditional wet season offensive in 1969 , the Air Force approved a major offensive bombing campaign within " Barrel Roll " named " Raindance " . It was timed to coincide with spoiling operations that Vang Pao had planned against the Plain of Jars . The operation began on 17 March and launched 80 strikes per day for 12 days . " Raindance " was extended through 7 April , by which time 730 U . S . sorties had been flown . On 22 May the Air Force conducted " Stranglehold " , a five - day campaign focused on Routes 6 and 7 , PAVN ' s logistical lifeline . Regardless , the North Vietnamese launched " Campaign Thoan Thang " ( Total Victory ) during late June and managed to take Moung Soui with the assistance of armoured units . A total of 103 Air Force and 44 AT - 28 strikes were flown in the defense of the town , but to no avail . Part of the PAVN success could be attributed to the record number of its units then available in the northeast . Seven new battalions having arrived since April . In June , William Sullivan was replaced as ambassador by G . McMurtrie Godley , who immediately loosened the rules of engagement and increased the bombing campaign in the north and northeast . The results were almost immediate . Nearly 50 percent of the population of the once heavily populated Plain of Jars had moved into refugee camps in the south . Refugee rolls for the Agency for International Development , which had averaged 130 , 000 between 1964 and 1968 , jumped to 230 , 000 in February 1970 . On 6 August 1969 , in Military Region 2 , Hmong forces launched a major counterattack ( the " Kou Kiet " [ Redeem Honor ] Campaign ) against the communists on the Plain of Jars and in the Xieng Kouang area , supported by its own air units and the U . S . Air Force . The offensive was a success due not to American airpower , but to unseasonably rainy weather . 46 inches ( as opposed to the normal 16 ) fell in July , cutting sharply into the communist logistical flow . After the weather broke , the Hmong were supported by 145 sorties per day . Communist forces , cut off from resupply , fled to the west . For the first time since 1961 all of the strategic Plain of Jars was under government control . This course of events led Ambassador Sullivan to declare : " We believe that damage to the enemy represents the best results per sortie by tactical air in Southeast Asia . " That summer , sorties throughout the " Barrel Roll " area had risen from an average of 300 missions per month to an average 200 sorties per day . On the defensive ( 1970 – 1972 ) . Beginning of the end . The nature of the conflict in the northeast changed radically in mid - September 1969 , when the communists were reinforced by the remaining two regiments of the 312th Division ( the 165th and 209th ) , the refitted 316th Division , the 866th PAVN Infantry Regiment ] , the 16th PAVN Artillery Regiment , a tank company , six sapper and engineer battalions and ten Pathet Lao battalions . On 11 February 1970 , these units launched " Campaign 139 " , and by the 20th the Plain of Jars had been taken . Royal Lao forces withdrew to Muong Soui and five days later they abandoned Xieng Khouang . On 18 March Xam Thong fell and Vang Pao ' s stronghold at Long Tieng was threatened . As a stopgap , Washington approved Operation " Goodlook " , the first usage of Boeing B - 52 Stratofortress bombers in northern Laos . During the first mission on 18 February 36 bombers delivered 1 , 078 tons of bombs . On 25 April the battered communist forces fell back , but the 316th PAVN Division and the 866th PAVN Infantry Regiment remained behind to assist the Pathet Lao . A CIA study concluded during the year that " About the most positive thing that can be said about Laos is that it still exists as a non - communist state . " Souvannah Phouma was then 69 years old , visibly losing his vigour , and he had no apparent successor . The see - saw , seasonal conflict dragged on , but at the end of each cycle , the balance was somewhat more favorable to PAVN and the Pathet Lao . Due to the withdrawal of U . S . forces under the policy of Vietnamization , from 1 November 1968 until 23 February 1973 , " Barrel Roll " competed for a share of diminishing U . S tactical air assets . In December 1968 , approximately 700 American strike aircraft had been available in - theater . By the spring of 1972 , that number had fallen to 313 . On 18 July , the Nakhon Phanom - based 22nd Special Operations Squadron was disbanded . Its sister squadron , the 602nd Special Operations Squadron , closed out on 20 December , leaving only the 1st Special Operations Squadron at Nakhon Phanom to support Royal Laotian ground operations . The Royal Laotian Air Force attempted to make up for the diminishing number of American sorties . During 1968 the Laotians flew 10 , 000 strike sorties . During 1970 through 1972 that number increased to over 30 , 000 in each year . Under the existing command and control arrangement between the CIA , the AIRA , and the Seventh Air Force , the Air Force wielded little actual control over air support . In order to increase its dominance , a reduction in the role of the Raven FACS was called for . Instead , greater use was to be made of " Nail " FACs from Nakhon Phanom ' s 23rd Tactical Air Support Squadron which had recently begun transitioning to OV - 10 Bronco aircraft . In the end , the " Nails " made increasing appearances over Military Region 2 , but they never seriously encroached on the role of the Ravens . On 2 February 1971 North Vietnamese and Pathet Lao forces launched their dry season offensive ( " Campaign 74B " ) to recapture the Plain of Jars . PAVN forces taking part in the operation included the 316th Division , the 165th Regiment of the 312 Division , the 866th Infantry Regiment , and three sapper battalions ( the 13th , 27th , and 41st ) . Communist forces rolled west and southwest , gobbling territory in anticipation of a possible cease - fire . By February they had occupied the entire Plain of Jars , Long Tieng had been surrounded , and , for the first time since 1962 , Pathet Lao forces were camped within sight of the royal capital of Luang Prabang . Ominously , PAVN and the Pathet Lao did not withdraw to North Vietnam during the rainy season . Previously during the conflict , air mobility by contract aircraft and the Lima Sites had provided the Hmong with an advantage over the road - bound PAVN and Pathet Lao forces . This advantage was now going to be overcome by road improvement and the prepositioning of supplies which allowed the communists to maintain year - round use of their lines of communication . The American command in Saigon and the politicians in Washington were opposed to a wet season Hmong offensive , supporting instead a holding action on the edge of the Plain of Jars as a prelude to a possible cease - fire . Washington also insisted that U . S . airpower be used to interdict PAVN supply lines , not as close air support for ground operations . Vang Pao took up the offensive anyway , but his forces could only occupy half of the plain before his offensive sputtered out at the end of July . There was also a growing public awareness in the U . S . of military activities in Laos . During October 1969 , Senator Stuart Symington ( D - MO ) chaired hearings of the Subcommittee of the Senate Foreign Relations Committee on Security Agreements and Commitments Abroad . The testimony of subpoenaed witnesses revealed the history of U . S . involvement in the covert commitment to Laos . Due to the closed nature of the sessions and its heavily censored transcript , however , the nature and extent of that commitment was still very little understood by the American public . That changed , however , with the publication of the " Pentagon Papers " , which disclosed the earliest stages of " Yankee Team " , " Barrel Roll " , and the Thai commitment . President Richard M . Nixon was eventually forced to disclose the extent of U . S . participation , which further weakened ability of the U . S . to respond to the increasing PAVN and Pathet Lao threat . The spring of 1972 was not a happy one in either Washington or Vientiane . A U . S . Congressional delegation , after investigating the situation on the ground in Laos , reported that " No one we met in Laos , American or Lao , seemed to have any prescription for the future other than to continue what ' s being done now . " Running out of resources . Vietnamization was catching up with the conflict in Laos . During the 1970 – 1971 dry season , U . S . Air Force strike missions in support of Hmong operations had dropped by 70 percent from the previous year from 114 sorties per day to 38 . The grinding nature of the conflict was also having a cumulative effect on the adult male population of the Hmong . Severe attrition had forced the Hmong into a numbers game that they could not win . In March 1971 South Vietnamese forces , supported by U . S . air power , launched Operation " Lam Son 719 " , the long - awaited offensive to cut the Ho Chi Minh trail in southeastern Laos . However , the result was a failure . North Vietnamese and Pathet Lao forces has already began to expand the trail system westward , pushing Royal Lao forces toward the Mekong , slowly extending the territory it controlled , moving west of the trail and creating a larger buffer zone between its logistical system and the South Vietnamese . After " Lam Son 719 " , that process accelerated . Hanoi ' s effort was simplified by the fact that the Royalist forces in the south had little experience fighting PAVN and they were quickly overwhelmed . Inept and ineffective were terms utilized to describe their defense . On 30 April 1971 the key town of Attopeu was seized by the communists . Vang Pao himself was not blind to the realities facing his people . He had threatened to launch a mass migration of the Hmong to Thailand on three previous occasions . In November 1969 , he tried a different tack , contacting the Pathet Lao and attempted to negotiate a quid pro quo : the Hmong would cease fighting if the communists would allow them to establish a semiautonomous state in Xieng Khouang Province . The diminishing number of troops available to Vang Pao demanded their replacement by growing numbers of Thai volunteers ( Project " Unity " ) , who increasingly took over the ground war in the north . By the end of 1971 , the entire 55 - man battalion of Thais were in action , whose total numbers were 6 , 000 – 8 , 000 men . During the following year , those numbers had ballooned to 17 , 800 . The total force eventually deployed was three artillery and 27 infantry battalions . Withdrawal ( 1972 – 1975 ) . Talking and fighting . By October 1971 Prince Souvannah had little alternative but to accept the Pathet Lao program as the basis for negotiations . The Pathet Lao agreed to the new negotiating effort and on 14 October , representatives of the party arrived in Vientiane . Two weeks later they were followed by Phoumi Vongvichit , secretary general of the Pathet Lao . Communist demands included : a cessation of the U . S . bombing of Lao territory ; withdrawal of all U . S . advisors and military personnel ; an election for a new National Assembly ; the establishment of a coalition government ; and compensation and resettlement for those Lao who had been forcibly relocated would be undertaken . The pace of negotiations in Laos , however , mirrored those in South Vietnam , the impetus of which was determined by the perceived military success of the protagonists . The dreaded North Vietnamese wet season offensive ( " Campaign Z " ) began on 17 December 1971 . The multi - division offensive was commanded by Major General Le Trong Tan , who had commanded the PAVN counteroffensive against Operation " Lam Son 719 " . Once again the communists rolled across the Plain of Jars and to the outskirts of Long Tieng . This time however , they had brought along a battery of 130mm artillery , which proceeded to pummel the defenders . By 17 January 1972 , reinforcement by Unity troops and strikes by B - 52s had driven the North Vietnamese from the high ground surrounding the valley , but they could not be pushed out of the area . General Tan then shifted the focus of his forces to the southwest and seized Sam Thong on 18 March . The fighting around Long Tieng did not cease until 28 April . On 21 May 1972 Royal Lao and Hmong forces , supported by air strikes , attempted to retake the Plain of Jars . The fighting raged for 170 days ( until 15 November ) , but the communists could not be evicted . PAVN and the Pathet Lao claimed to have killed 1 , 200 enemy troops and to have captured 80 . The communists made additional gains during the year , but failed to overwhelm government forces . The launching of PAVN ' s " Nguyen Hue Offensive " in April 1972 had the effect of returning major American air assets to the theater and eventually increased the tempo of operations in northeastern Laos . As a result , Royal Lao armed forces , Hmong , and Thai mercenaries went on the offensive , as did PAVN and the Pathet Lao , all of whom wished to become " well postured for the peace negotiations . " Although there was no provision for a Laotian cease - fire written into the Paris Peace Accord that was signed on 27 January 1973 , it had been verbally agreed between the U . S . and North Vietnamese representatives that one would be instituted within 15 days of the signing of the agreement . The fates of Laos and Cambodia were disposed of in Article 20 of the agreement , in which the North Vietnamese and the U . S . promised to respect the neutrality of both nations and to end their military intervention . Unfortunately , there was no means by which to enforce the agreement . That the North Vietnamese would uphold it , after violating two previous neutrality accords , " took optimism bordering on an act of faith that they would now abandon the ambitions and struggles of thirty years because of a clumsily drafted afterthought in a document they had no intention of honoring anyway . " The Americans were pulling out of Southeast Asia as quickly as negotiations with the North Vietnamese would allow them . Ambassador Godley , stunned by the diplomatic developments , ruminated that " We had led him ( Souvanna ) down the garden path . Let ' s face it , we were cutting and running . . . Once we were out of Vietnam the only way we could have protected Laos was with an Army corps . It was totally out of the question and we knew it . We were licked . " Souvanna then faced a dilemma , sign a separate agreement with the Pathet Lao on almost any terms , or continue the war with no prospect of success . Hanoi was also desirious to obtain a quick agreement with Vientiane . The sooner the fighting in Laos ceased , the sooner the Hanoi would obtain unimpeded use of the Ho Chi Minh trail . On 21 February , Souvanna signed an Agreement on the Restoration of Peace and Reconciliation in Laos between the central government and the Pathet Lao . The agreement was preceded by intense fighting , as both sides attempted to seize as much territory as possible before the cease - fire went into effect . The agreement was moot , however , since Hanoi had no intention of removing its troops or abandoning its logistical system . Cease - fire . The cease - fire went into effect on 22 February 1973 . Not all of the fighting , however , had ended . This was particularly true around the town of Paksong , the last Royal Laotian stronghold on the Bolovens Plateau – the strategic high ground overlooking the Mekong River . At the request of Souvanna , nine B - 52s and 12 U . S tactical fighters struck the outskirts of the town on 24 February . By mid - month , the bombers had flown 1 , 417 sorties and struck 286 targets in northern Laos . Once again acceding to a request from Souvanna , B - 52s returned for two more days of bombing on 16 and 17 April , dropping ordnance in support of government forces under attack around Ban Tha Vieng on the Plain of Jars . On 5 April 1974 a coalition government was finally established by a royal decree with Souvanna as president . Due to the defeatism and political deterioration of the rightists within the kingdom , the Pathet Lao moved adroitly , slowly preempting the government and military and soon winning a surprising popularity among the Lao population . On 4 June , as per the agreement , all U . S . and Thai personnel left the country , leaving 50 – 60 , 000 North Vietnamese troops still ensconced within Laos . The previous month an airlift had begun at Long Tieng which evacuated as many of the Hmong as possible to Thailand . They were soon followed by approximately 40 , 000 others who set out on foot for exile . On 2 December 1975 the coalition government and the monarchy were abolished by the provisional government , which then disestablished itself . The Lao People ' s Democratic Republic then came into existence . Conclusion . For 100 months , the U . S . Air Force , the CIA , and the Thai government had assisted the Royal Lao government in staving off defeat at the hands of its enemies . If one measures the success of " Barrel Roll " by the priorities assigned to it by the U . S . government and military , it was a success . It had allowed the continuous prosecution of the " Steel Tiger " ( and , post - 1968 , Operation Commando Hunt ) interdiction campaigns against the Ho Chi Minh trail by keeping the neutralists in power . At the time of the cease - fire , communist forces controlled two - thirds of the land area and one - third of the population of Laos , approximately the same amounts that they had under their control in 1961 . The imposition of a strategic stalemate had prevented the fall of the Vientiane government , which accomplished the secondary goal of the operation , protecting Thailand from communist attack ( however unrealistic that threat appears today ) . This stalemate had been achieved with the loss of 131 U . S . aircraft between 1964 and 1973 , a very low loss rate when compared to the operations discussed above . For the U . S . Air Force , this success was achieved by conducting a shoestring operation , one that was fourth in priority for American air assets behind operations in South Vietnam , Operation " Rolling Thunder " , and " Steel Tiger " . After the close - out of aerial operations over North Vietnam , " Barrel Roll " still remained in last place . During its existence the campaign had utilized an average of only ten percent of the Air Force ' s tactical air effort in Southeast Asia . During the 1972 " Nguyen Hue " PAVN offensive , the number of airstrikes over northern Laos was reduced to only five percent of the total . There were problems . Inflated bomb damage assessment reports during operations in northeastern Laos were common , but the cause was not difficult to discern . Mountainous terrain , poor weather , ground cover , the lack of ground forces for confirmation , and the language barrier all contributed to overestimation of the damage inflicted on communist forces by the bombing effort . The result was a skewed sense of the effectiveness and the capabilities of the campaign . The results of the campaign ( which were made obvious by the repeating seasonal nature of PAVN and Pathet Lao offensives ) , however , indicated that American airpower was quite effective . But this success was achieved at a tremendous cost for the Laotians . After the onset of the withdrawal of American forces from South Vietnam in 1969 , Laos ( and , after 1970 , its neighbor to the south , Cambodia ) were doomed to defeat . There was little , if any , possibility for the indigenous forces of either nation to defeat the external threat once the U . S . had completed the process . The fratricidal conflicts in both nations were escalated and encouraged by the U . S . in order to buy time for its withdrawal and the prolonged existence of the Republic of Vietnam . The covert war in Laos continues to fascinate those with any knowledge of it . It was one of the quintessential Cold War insurgency / counterinsurgency , low - intensity conflicts and offers many lessons in the conduct of irregular covert operations supported by modern military technology . It also remains one of only a few military operations of the Vietnam War about which both major belligerent parties ( the U . S . and North Vietnam ) are still reluctant to openly discuss their participation . For the North Vietnamese , this is understandable . Hanoi has no more incentive to discuss its operations today than it had in the 1960s or 1970s . Although the U . S . has been more open about its participation , the covert war remains a touchy subject : it has been called " nightmarish synthesis of total war and colonialism , a war in which two of the most deadly manifestations of twentieth century violence culminate " .