Beginning in the early 1960s, communist North Vietnam (The Democratic Republic of Vietnam, or DRV) began sending arms and reinforcements to the guerrillas of the National Liberation Front (NLF) fighting a war of reunification in South Vietnam. To combat the NLF and shore up the regime in the south, the United States sent advisors, supplies and combat troops. A war escalated that would see American soldiers engaging NLF insurgents and North Vietnamese regular troops in the field.
The supply lines for the war ran south across the demilitarized zone (DMZ) separating North and South Vietnam, or via Laos and Cambodia along the infamous ‘Ho Chi Minh Trail’. The source of these supplies was the People’s Republic of China and the Soviet Union. The road and rail network of the north was vital for transshipping materiel south. The hub of this network was the national capital, Hanoi.
In August 1964, the ‘Gulf of Tonkin Incident’, a skirmish between DRV and United States Navy ships, gave the US a pretext to launch air strikes against the North. The objective, outlined by President Lyndon B. Johnson, was to discourage further “communist aggression” by launching punitive attacks against the DRV.
In late 1964 the Joint Chiefs of Staff drew up a list of targets to be destroyed as part of a coordinated interdiction air campaign against the North’s supply network. Bridges, rail yards, docks, barracks and supply dumps would be targeted. However, President Johnson feared that direct intervention by the Chinese or Russians could trigger a world war and refused to authorize an unrestricted bombing campaign. Instead, the attacks would be limited to targets cleared by the President and his Secretary of Defense, Robert S. McNamara.
Beginning in 1965 Rolling Thunder was a sustained bombing campaign against North Vietnam. Early missions were against the south of the DRV, where the bulk of ground forces and supply dumps were located. Large-scale air strikes were launched on depots, bases and supply targets, but the majority of operations were “armed reconnaissance” missions in which small formations of aircraft patrolled highways and railroads and rivers, attacking targets of opportunity.
Afraid the war might escalate out of hand, Johnson and McNamara micromanaged the bombing campaign from Washington. Rules of Engagement were imposed to limit civilian casualties or attacks on other nationals, such as the Eastern Bloc-crewed supply ships in Haiphong harbor or the Soviet and Chinese advisors helping train the Vietnamese military.
However, the American policy of ‘graduated response’ – slowly ramping up pressure on the DRV leadership – meant that more targets became available to airmen to bomb. The bombing moved progressively northwards toward Hanoi. Exclusion zones were maintained around Hanoi and Haiphong to keep bombers away from the population centers, but eventually raids would be authorized even into these sanctuaries.
To keep the United States Air Force and Navy out of each other’s way the DRV was divided into air zones called ‘Route Packages’ (RPs), each assigned to a service. The area around Hanoi included Route Packages 5 and 6a (the USAF’s responsibility) and 4 and 6b (the USN’s). Strikes into RP 6a or 6b were reckoned to be the toughest of all. The Vietnamese, with Soviet and Chinese help, had built a formidable air defense system there. Initially this consisted of anti-aircraft artillery (AAA) and MiG fighter jets, but from mid-1965 this was supplemented by surface-to-air missiles (SAMs). A radar net now covered the country that could track incoming US raids and allocate SAMs or MiGs to attack them.
To survive in this lethal air defense zone the Americans adopted special tactics. Large-scale raids were assigned support aircraft to keep the bombers safe. These would include fighters to keep the MiGs away, jamming aircraft to degrade enemy radars, and ‘Iron Hand’ fighter-bombers to hunt down SAMs and suppress AAA. New electronics countermeasures devices were hurriedly deployed to protect aircraft from missile attacks.
By 1966 the air war in the higher Route Packages was getting hotter. Though most of the casualties came from AAA, there were an increasing number of encounters with SAMs and MiGs. MiGs were a particular problem because the Americans’ poor radar coverage of the Hanoi region allowed obsolete jets such as the MiG-17 to get the jump on them. Airborne Early Warning aircraft had great trouble detecting MiGs at very low altitude.
Most of the USAF raids against the North came out of bases in Thailand. They would refuel over Laos before flying onto their targets. Sometimes the Americans would fly low and use prominent terrain features such as Thud Ridge to mask them from radar as they approached. After attacking the target – usually by dive-bombing – the raid would either head directly back to Thailand or exit over the relatively safe waters of the Gulf of Tonkin.
Navy raids would be launched from TaskForce 77’s carriers cruising on Yankee Station. The complement of a carrier air wing was needed to form an ‘Alpha Strike’. The Navy aircraft would usually take the shortest way into and out from the target.
Bombing halts became a feature of the war. Some of these were politically enforced, as President Johnson tried a ‘carrot and stick’ approach to coax the DRV into a peace agreement. Others were the fault of the weather that for six months a year made bombing near impossible. Attempts were made to overcome the weather by developing blind bombing techniques using radar or radio navigation systems, but at best they generated mediocre results and were often useless. 1967 saw America’s most intense and sustained attempt to force the Vietnamese into peace talks. Almost all the Joint Chiefs’ target list was made available to be attacked, and even airfields – previously off-limits – came in for a pasting. Only the center of Hanoi (nicknamed ‘Downtown’ after the Petula Clark song) and Haiphong harbor remained safe from harm. The Vietnamese reacted by becoming more aggressive with their MiGs and using AAA and SAM to rack up an impressive tally of US aircraft.
After two years of bombardment the Vietnamese were well equipped to handle US raids, having dispersed their supplies and developed the means to repair and rebuild the supply network after the raids had passed. Their strategy was longsighted. They didn’t have to defeat the Americans, merely absorb the punishment and outlast them.
By 1968 McNamara had become convinced that airpower could not win the war. In spite of the air campaign the Tet New Year holiday saw Hanoi and the NLF mount an offensive in the south. The Tet Offensive was a military disaster for the North and their NLF allies, but it still broke the will of the American leadership. Hoping that Hanoi would enter into peace talks, President Johnson offered a bombing halt. The communists, licking their wounds after Tet, agreed to talks and the Rolling Thunder campaign came to an end.