Before their attacks across South Vietnam, communist forces sowed confusion among their enemies through a massive disinformation campaign
On Jan. 31, 1968, the start of a cease-fire for the Lunar New Year celebration called Tet, the Viet Cong and North Vietnamese Army launched large-scale assaults across South Vietnam. Even though the communists had conducted seven major attacks in the northern and central regions the previous day, most senior American and South Vietnamese political leaders and mid-to-senior level military officers were away for the holiday. Surprised and paralyzed, most South Vietnamese units responded slowly, enabling the Viet Cong to seize their initial objectives.
The early successes of the communists’ Tet Offensive, intended to spark a national uprising that would overthrow the Saigon government, rudely shocked the American public and congressional leaders who had been treated to months of optimistic statements from President Lyndon B. Johnson’s administration and military commanders. The breadth and scale of the offensive discredited the government’s claims that the Viet Cong were on the verge of defeat. It seemed as if America’s intelligence agencies and political leaders were either delusional or dishonest.
In the end, the communists suffered a costly defeat on the battlefield, but Tet gave them a political victory that would lead to a U.S. military withdrawal seven years later.
The outcomes of the offensive can be traced to a combination of strategic decisions in Washington, Hanoi and Saigon; conflicting intelligence information that hobbled Washington and Saigon; and Hanoi’s effective deception operations that were incorporated into plans for a “general offensive-general uprising.”
Leaders in all three capitals believed the war was going their way, but none had a unified view of the road ahead. As South Vietnam’s scheduled November 1967 elections approached, Saigon’s leaders were more concerned with internal political disputes than with the war itself, and some resented the United States’ domination of the tactical and operational planning. Similarly, with a U.S. presidential election looming in November 1968, rising casualties had increased opposition to the war and provided an incentive for Johnson and the Pentagon to present a rosy view of the military’s campaigns.
Divisions also wracked Hanoi as 1967 advanced. President Ho Chi Minh, NVA commander Gen. Vo Nguyen Giap and their loyalists favored a patient, long-struggle guerrilla warfare insurgency in South Vietnam. However, they were being shunted aside by Communist Party General Secretary Le Duan and his protege, Gen. Nguyen Chi Thanh, who favored a rapid conquest by large-scale offenses but faced growing criticism over mounting casualties and the lack of visible progress in the South.
Recruiting for Viet Cong units was down; defections and desertions were rising. To fill those gaps, “main force” (professional, full-time) VC units were bolstered by NVA soldiers, female volunteers or conscripts. Le Duan and Thanh believed the losses and morale problems were secondary to evidence that South Vietnam was ripe for a rebellion because of the political turmoil there since the November 1963 assassination of President Ngo Dinh Diem and the rising resentment of the American presence.
Giap was less confident of an uprising (Ho’s thoughts at that time are unclear) and published his views in Communist Party organs, arguing the wisdom of a prolonged struggle and advising party leaders to temper expectations of a quick victory. But Le Duan was now in control of the war’s geopolitical policies and strategy. Thanh died in July 1967, and Le Duan promoted Senior Gen. Van Tien Dung to direct the military planning and execution of the Tet Offensive. Giap nominally had oversight authority and retained some influence in the planning; however, Dung reported directly to Le Duan.
Although Ho’s influence was diminished, his emphasis on political warfare and knowledge of American political principles dominated Hanoi’s strategic planning and deception tactics. Pre-offensive political warfare operations had two goals: 1) persuade Washington to end its bombing and offensive operations as a path to peace; 2) divide the U.S. and South Vietnam by exploiting their mutual distrust.
As Le Duan saw it, if Johnson, a reluctant war leader, took the bait and grasped at the chance for a peace deal, North Vietnam could then intensify Saigon’s distrust of American leaders by generating rumors that the U.S. was considering a postwar coalition government with key positions set aside for the Saigon government’s arch enemy, the communist and Hanoi-led National Liberation Front, a political organization with a military component and more commonly known as the Viet Cong.
North Vietnam’s Politburo approved the Tet Offensive on July 26, 1967. The political deception began in August, with Le Duan raising the pressure on Johnson through propaganda targeting the American public and world opinion. In that campaign, Le Duan enjoyed intelligence superiority. Hanoi’s leadership possessed far greater knowledge of the dynamics of American democracy and Washington’s power structure than Washington’s leaders had of Hanoi’s politics.
Although Ho Chi Minh remained president, Le Duan had stripped him and Giap of their party offices in December 1960 and by November 1963 had assumed complete control of the Communist Party. Amazingly, until 1969 the CIA listed Le Duan as fourth in Hanoi’s power structure behind Ho, Giap and Premier Phạm Van Dong.
The CIA correctly believed that Ho and Giap wanted to reduce the level of combat in the insurgency but wasn’t aware their influence had waned. The Johnson administration was still appealing to a Hanoi “peace faction” that had been crushed. Le Duan spent 1967 purging or imprisoning those who favored peace talks. Ho and Giap were spared, but their loyalists were not.
In August 1967, Le Duan ordered an increase in public reporting of North Vietnamese civilian casualties from American bomb drops, invited Western celebrities and “opinion leaders” to view the damage and released films depicting real and manufactured destruction. Meanwhile, disinformation agents used their media contacts in Western and nonaligned nations to spread rumors of Hanoi’s willingness to enter peace talks, further encouraging the growing anti-war movement and creating more headaches for Johnson.
Recognizing that South Vietnamese or U.S. forces might capture some Viet Cong civilian leaders—“political officers” implanted in villages—and discover VC documents, Hanoi dispatched “walk-ins” who approached the allies with contrary intelligence and other disinformation. For example, in September 1967 captured VC political officer Ha Sua told the South Vietnamese he had been sent to open negotiations with U.S. officials. Sua provided documents listing the topics to be discussed, including the good-faith release of VC prisoners. The ruse convinced the Johnson administration to pressure Saigon into releasing several high-value VC officials and send a letter via Sua to start talks. Hanoi’s rumormongers used that as “proof” the U.S. was seeking a peace agreement that shut out Saigon.
The detailed politico-military planning for Tet involved only a handful of Communist Party officials and key deputies of Giap and Dung. The National Liberation Front held a secret congress in August 1967 to develop a program to expand popular support in South Vietnam and increase sympathy in the international media. Dissemination was limited to senior congress members until November.
Meanwhile, Dung intensified VC political officer training and indoctrination to restore morale. He also accelerated the modernization of NVA and VC military units and stepped up the training of special forces.
As part of the deception, communist communications related to the offensive were restricted to low-power VHF radio signals, buried landlines and couriers whenever possible. However, NVA division headquarters used powerful high-frequency transmitters in Cambodia to communicate with their higher headquarters, knowing that those electronic communications—signals intelligence—would be intercepted by the Americans and give the false impression that enemy operations were concentrated along the border with Cambodia, the Laotian border and the Demilitarized Zone separating North and South Vietnam. NVA attacks in those areas seemingly corroborated the evidence that Hanoi intended to continue its existing focus on battles in the border areas.
Dung also strengthened operations security and camouflage along the Ho Chi Minh Trail. North Korea’s Kim Il-Sung had advised Hanoi in 1961 that tunneling was the best way to thwart American air power and intelligence collection. The tunneling was far from complete in 1967, but units moving south enjoyed significant cave and tunnel rest areas for the first 250 miles of their journey. They moved only at night and used camouflage in areas lacking underground shelters. But American sensors and aircraft that collected signals intelligence were beginning to penetrate the veil of secrecy protecting the trail’s traffic, and airstrikes were inflicting heavier losses. Dung responded by nearly doubling the strength of the unit responsible for the trail, the 559th NVA Division, and raising its anti-aircraft artillery strength to over 1,200 guns.
An NVA intelligence agent inserted in the South Vietnamese prime minister’s office was present when the prime minister received briefings on the Ho Chi Minh Trail
reconnaissance missions of an elite covert operations unit, the Military Assistance Command, Vietnam-Studies and Observations Group. In the summer of 1967 the NVA’s 559th Division conducted company and later battalion-sized sweeps along the trail to find American reconnaissance teams and sensors. Hanoi also initiated a study of MACV-SOG operations to identify their patterns, preferred moonlight and weather conditions, and landing zones.
Dung set the offensive’s launch date for Feb. 8, 1968, and limited dissemination of the overall plan to the Central Office for South Vietnam, which coordinated communist political and military operations from a headquarters that was in Cambodia at the time but moved frequently to prevent detection. The exact date was excluded from documents distributed to lower-echelon units, which were simply ordered to be “ready” by February. Those units only knew their assigned area.
In another act of deception, Giap’s articles advocating the long struggle and insurgency tactics were published to show evidence of a return to guerrilla actions.
Giap’s intelligence chief, Senior Col. Le Trong Nghia, recruited hundreds, especially women, to seek jobs around American and South Vietnamese military facilities with a particular emphasis on bases hosting headquarters and intelligence facilities.
He also ordered at least three attacks on South Vietnamese and joint intelligence processing centers and the Phu Bai radio intercept site. Documents captured after two of the attacks revealed that the communists possessed very detailed knowledge of one processing center, including analyst identities, and the Phu Bai site, where they knew specific seating and work assignments.
During sweeps around Saigon and Pleiku in the Central Highlands, South Vietnamese police and U.S. troops seized VC arms shipments and captured loads of documents related to Hanoi’s agent recruiting and promises of a coming revolt. American units also seized planning documents in Ia Drang Valley battles and fighting around Khe Sanh and Con Thien, near the DMZ. However, the dissemination and translation of those documents was too slow to counter the signals intelligence that misleadingly indicated a spring offensive in northern South Vietnam and along the Cambodian border.
In July 1967, MACV commander Gen. William Westmoreland had identified a spring 1968 countrywide offensive as his greatest concern, but MACV’s assessment ran counter to the prevailing view in Washington—in part because of the general’s own monthly reports suggesting U.S. operations were devastating the Viet Cong. Surely, a weakened enemy wasn’t capable of a countrywide offensive.
Adding to the disunity, Westmoreland and his staff were embroiled in a dispute with the CIA about estimates of enemy strength. MACV measured enemy strength by the number of main force, full-time VC soldiers, while the CIA’s numbers incorporated part-time combatants who could be called up for specific operations.
Main force units were losing strength, but losses among part-time soldiers were more difficult to measure. More important, MACV believed that part-time VC soldiers couldn’t stand up to conventional combat, making them almost irrelevant, but the CIA argued that they were effective enough to conduct acts of sabotage, hit-and-run raids, ambushes and assassinations.
MACV and the Pentagon were concerned that adding part-time soldiers to the official count would almost double the number of enemy troops being reported, politically damaging if leaked to the public after months of claiming that enemy strength was declining. The compromise reached on Sept. 14 excluded part-time VC numbers but admitted as much.
There also was debate over the state of North Vietnam’s war effort. Most analysts believed Hanoi’s strategy had not yet reached the point where a guerrilla insurgency turned into large-scale conventional military actions. This view was reinforced by the early summer drop in Viet Cong attacks inside the South and a midsummer’s reduction in enemy activity everywhere except South Vietnam’s northernmost provinces.
The Marines at Con Thien suffered almost daily artillery, rocket and mortar attacks, and those at Khe Sanh encountered growing numbers of NVA troops. Westmoreland’s Operation Neutralize drove the North Vietnamese out of the DMZ by late November, but Hanoi’s forces continued their buildup in Laos near Khe Sanh.
Intelligence analysts believed an August increase in VC attacks and troop concentrations around Dak To in the Central Highlands was intended to disrupt South Vietnam’s September elections. A post-election lull in attacks seemingly confirmed that analysis, although the NVA launched five major assaults out of Cambodia in November and two in northern South Vietnam. U.S. analysts dismissed reports of NVA armor moving down the Ho Chi Minh Trail but believed that Hanoi was planning a major offensive in spring 1968, later amended to sometime after the Tet holiday. They thought the main objectives were in northern South Vietnam and the Central Highlands, not urban areas.
In late November, Dung advanced the Tet Offensive’s start date to Jan. 30.
U.S. Special Forces units operating in the Central Highlands during December 1967 reported main force VC troops moving southeast, but those troops couldn’t be found by either signals intelligence or aerial reconnaissance. At year’s end, the CIA station in Saigon issued an assessment that Hanoi was planning a nationwide offensive during or after Tet; however, neither MACV nor Washington were convinced.
In Hanoi, Le Duan expanded his purge, arresting all of Giap’s and Ho’s inner circle and more than 100 others suspected of favoring peace talks. Ho went to Beijing for medical treatment, and Giap traveled to Eastern Europe. Hanoi’s “peace faction” was now outside the country or imprisoned.
On Dec. 31, Le Duan introduced the political deception’s final phase with Foreign Minister Nguyen Du Trinh announcing that a bombing halt would lead to peace talks. Radio Hanoi repeated it the next day. Most of Johnson’s senior staffers distrusted Hanoi’s sincerity, but the president overruled them.
Johnson tightened restrictions on the U.S. bombing campaign, while Defense Secretary Robert McNamara pressured Westmoreland on Jan. 7 to extend the Tet cease-fire into mid-February and reduce military operations. Westmoreland objected, warning that an NVA buildup around Khe Sanh suggested an attempt to repeat the communist success 14 years earlier at Dien Bien Phu, the battle that ended French rule of Indochina. That argument persuaded Johnson to allow Westmoreland to act. But Westmoreland could not prevent Washington from urging the Saigon government to send half its troops home for Tet as a “peace gesture.”
The NVA’s 304th, 324th and 325C divisions approached Khe Sanh on Jan. 4, and the next two weeks saw an upsurge in communist activity. VC and NVA commandos attacked two South Vietnamese police stations in the Central Highlands and the Marine air station at Da Nang. An NVA artillery regiment rocketed Da Nang, and the 803rd Infantry Regiment and four artillery regiments attacked Con Thien.
Meanwhile, American and South Vietnamese forces uncovered more than 45 weapons caches within 30 miles of Saigon, but did not interpret them as part of a buildup for the offensive.
On Jan. 20, the NVA conducted a major assault at Khe Sanh. The next day Westmoreland unleashed a massive air campaign against the NVA around Khe Sanh, canceled the Tet cease-fire in northern South Vietnam and cut the cease-fire elsewhere from 48 to 36 hours (the evening of Jan. 30 to the morning of Feb. 1).
Alerted to the change, Dung moved the offensive’s start date to Jan. 31, but not all units received the order in time. American signals-intelligence stations intercepted the transmission and issued a Jan. 28 alert about an impending nationwide attack. The next day Saigon police raiding a meeting of VC political officers found audio tapes calling for an uprising on Jan. 31.
On Jan. 30, some communist forces prematurely attacked Da Nang and six provincial capitals in northern and central Vietnam, and MACV’s intelligence officer, Gen. Philip R. Davidson, warned Westmoreland that an attack on urban areas was imminent.
Two U.S. generals had already put their forces on alert: Charles P. Stone, commander of the 4th Infantry Division, eight days earlier; and Frederick Weyand, commander of forces in the Saigon area, two days earlier.
However, Saigon’s leadership and much of the MACV staff were slow to react. South Vietnamese President Nguyen Van Thieu had departed for the holiday as had all provincial chiefs, the South Vietnamese army’s general staff and virtually every division commander. Most relaxed after the premature Jan. 30 attacks were repulsed.
Westmoreland left for his quarters, and more than half of MACV’s senior intelligence officers headed to a party at the bachelor officer quarters. Not even a report of two VC battalions entering Hue in the northern region generated an alarm. Only the normal night shift was present at MACV when the offensive erupted at 3 a.m. on Jan. 31. No one notified the forward MACV headquarters or Marines near Hue until hours later. More than 1,100 Americans and thousands of Vietnamese died in the five weeks of fighting that followed.
Hanoi’s deception plan worked because the North Vietnamese enjoyed superior knowledge of their opponents. They exploited American misperceptions of Hanoi’s power structure. They penetrated Saigon’s senior circles and intelligence agencies, American bases, the Western media in South Vietnam and businesses catering to the U.S. military. Hanoi understood American reliance on photo reconnaissance, signals intelligence and technology. It used that knowledge to send misleading signals to U.S. analysts.
Like all successful deceptions, Hanoi’s plan created the intelligence picture its enemy hoped to see. A handful of American analysts understood Hanoi’s approach to war, but they were a minority presenting an unwanted message. Additionally, the Johnson administration’s failure to expand its Indochina intelligence effort, particularly linguist training, until late 1967 precluded translation of the most revealing captured documents until after Tet.
Thanks to the deception’s success, Tet exceeded Le Duan’s expectations for impact on America’s will to fight, although it took Hanoi weeks to realize the political victory because the offensive was an expensive military failure. The attacks did not incite a general uprising, fatally damage Saigon’s political will or inflict a massive defeat on South Vietnam’s army. Moreover, communist casualties broke the Viet Cong militarily and politically, forcing the North to assume the bulk of the fighting after Tet, even providing the majority of troops in VC main force units.
Unlike America’s political and military leadership, Le Duan faced no doubts about his actions. After blaming the offensive’s military failure on Giap, crushing all political opponents and intimidating others, he remained on course to conquer South Vietnam, building on the lessons of Tet to develop a better deception and political warfare plan that would be employed unsuccessfully in 1972 but victoriously in 1975.
Carl O. Schuster is a retired Navy captain with 25 years of service. He finished his career as an intelligence officer. Schuster, who lives in Honolulu, is a teacher in Hawaii Pacific University’s Diplomacy and Military Science program.
This feature originally appeared in the February 2020 issue of Vietnam magazine. To subscribe, click here.