The Easter Offensive, also known as the 1972 Spring–Summer Offensive (Vietnamese: Chiến dịch Xuân–Hè 1972) by North Vietnam, or the Fiery Red Summer (Mùa hè đỏ lửa) in South Vietnamese literature, was a military campaign conducted by the People's Army of Vietnam (PAVN) against a force consisting of the Army of the Republic of Vietnam (ARVN) and the United States military between 30 March and 22 October 1972, during the Vietnam War.
This conventional invasion (the largest since the crossing of 300,000 Chinese troops across the Yalu River into North Korea during the Korean War) was a radical departure from previous North Vietnamese offensives. The offensive was designed to achieve a decisive victory, which even if it did not lead to the collapse of South Vietnam, would greatly improve the North's negotiating position at the Paris Peace Accords.
The U.S. high command had been expecting an attack in 1972 but the size and ferocity of the assault caught the defenders off balance, because the attackers struck on three fronts simultaneously, with the bulk of the PAVN. This first attempt by North Vietnam to invade the south since the Tet Offensive of 1968, became characterized by conventional infantry–armor assaults backed by heavy artillery, with both sides fielding the latest in technological advances in weapons systems.
In the I Corps Tactical Zone, North Vietnamese forces overran the ARVN’s defensive positions in a month-long battle and captured Quảng Trị city, before moving south in an attempt to seize Huế. The PAVN similarly eliminated frontier defense forces in the II Corps Tactical Zone and advanced towards the provincial capital of Kon Tum, threatening to open a way to the sea, which would have split South Vietnam in two. Northeast of Saigon, in the III Corps Tactical Zone, PAVN forces overran Lộc Ninh and advanced to assault the capital of Bình Long Province at An Lộc.
The campaign can be divided into three phases: April was a month of PAVN advances; May became a period of equilibrium; in June and July the South Vietnamese forces counter-attacked, culminating in the recapture of Quảng Trị City in September. On all three fronts, initial North Vietnamese successes were hampered by high casualties, lack of fuel and the increasing application of U.S. and South Vietnamese air power. One result of the offensive was the launching of Operation Linebacker, the first sustained bombing of North Vietnam by the U.S. since November 1968. Although South Vietnamese forces withstood their greatest trial thus far in the conflict, as well as thwarting North Vietnam's goal of large territorial gains, the North Vietnamese accomplished two important goals: they had gained valuable territory within South Vietnam from which to launch future offensives and they had obtained a better bargaining position at the peace negotiations being conducted in Paris.
Despite repulsing the PAVN offensive, the ARVN victory was only achieved through with massive U.S. air support.
In the wake of the failed South Vietnamese Operation Lam Son 719, the Hanoi leadership began discussing a possible offensive during the 19th Plenum of the Central Committee of the Vietnam Workers' Party in early 1971. Convinced that they had destroyed South Vietnam's best units during Lam Son 719, by December, the Politburo had decided to launch a major offensive early in the following year. 1972 would be a U.S. presidential election year, and the possibility of affecting the outcome was enticing and there was increasing anti-war sentiment among the population and government of the U.S. With American troop withdrawals, South Vietnamese forces were stretched to breaking point along a border of more than 600 miles (966 km) and the poor performance of ARVN troops in the offensive into Laos promised an easy victory.
This decision marked the end of three years of political infighting between two factions within the Politburo: those members grouped around Trường Chinh, who favored following the Chinese model of continued low-intensity guerrilla warfare and rebuilding the north, and the "southern firsters" around Defense Minister Võ Nguyên Giáp, supported by First Party Secretary Lê Duẩn (both of whom supported the Soviet model of big offensives). The failure of the Tet Offensive of 1968 had led to a downgrading of Giáp's influence, but the victory achieved over South Vietnamese forces during the Laotian incursion brought Giáp's strategy back into the ascendant. Lê Duẩn was given responsibility for planning the operation but Giáp never rose to his former prominence, dealing chiefly with logistical matters and the approval of operational planning. The officer entrusted with the conduct of the offensive was the PAVN chief of staff, General Văn Tiến Dũng.
The central questions then became where and with what forces the offensive would be launched and what its goals were to be. North Vietnam had used the border regions of Laos and Cambodia as supply and manpower conduits for a decade and a demilitarized zone (DMZ) that separated the two Vietnams. There, the line of communication would be shortest and forces could be concentrated where "the enemy is weakest...violent attacks will disintegrate enemy forces...making it impossible for him to have enough troops to deploy elsewhere." This was an important consideration, since the northern thrust would serve to divert South Vietnamese attention and resources, while two other attacks were to be launched: one into the Central Highlands, to cut the country in two and another eastwards from Cambodia to threaten Saigon.
The offensive was divided to four campaigns: Trị Thiên campaign in I Corps, Bắc Tây Nguyên campaign in II Corps, Nguyễn Huệ campaign in III Corps, and Nguyễn Huệ II campaign in IV Corps.
The campaign eventually employed the equivalent of 14 divisions. There was the distinct possibility of destroying or at least crippling large elements of the ARVN; possibly deposing of South Vietnamese President Nguyễn Văn Thiệu; convincing the U.S. as to the hopelessness of continued support to the South and demonstrating the failure of Vietnamization. The prospect of seizing a South Vietnamese provincial capital, which could then be proclaimed as the seat of the Provisional Revolutionary Government, was also enticing. The attitude of the North Vietnamese leadership was illustrated in an article in a 1972 party journal: "It doesn't matter whether the war is promptly ended or prolonged...Both are opportunities to sow the seeds; all we have to do is to wait for the time to harvest the crop."
The northern leadership was taken aback during the summer of 1971, when an announcement was made that U.S. President Richard Nixon would visit the People's Republic of China, on a diplomatic mission before May 1972. The Chinese placated the suspicions of their ally, by reassuring North Vietnam that even more military and economic aid would be forthcoming in 1972. The Soviet Union, perceiving the growing antagonism between the People's Republic and North Vietnam, sought to widen the rift by also agreeing to "additional aid without reimbursement", for North Vietnam's military forces.
These agreements led to a flood of equipment and supplies necessary for a modern, conventional army. This included 400 T-34, T-54 and Type 59 (a Chinese version of the T-54) medium and 200 PT-76 light amphibious tanks, hundreds of anti-aircraft missiles, including the shoulder-fired, heat-seeking SA-7 Strela (called the Grail in the West), anti-tank missiles, including the wire-guided AT-3 Sagger and heavy-caliber, long-range artillery. To man the new equipment, 25,000 North Vietnamese troops received specialized training abroad, 80 percent of them in the Soviet Union or Eastern Europe. A contingent of high-level Soviet military personnel also arrived in Vietnam and stayed until March 1972 in preparation for the offensive.
During late 1971, U.S. and South Vietnamese intelligence estimates of communist intentions were mixed. An offensive was expected, but intelligence as to its timing, location, and size were confusing. The communists had mounted the Tet Offensive in 1968, but it had been conducted mainly by Vietcong (VC) in the initial phase, which had been destroyed in the process. Without VC support, a large-scale PAVN offensive was considered highly unlikely. A PAVN thrust across the DMZ was also considered unlikely. Past infiltration and offensive operations had been conducted through and from Laotian and Cambodian territory and a DMZ offensive would be a blatant violation of the Geneva Agreement, which North Vietnam was adamant in defending.