The Eastertide Offensive began when 200,000 North Vietnamese soldiers under the command of General Vo Nguyen Giap waged an all-out attempt to conquer South Vietnam on March 30, 1972.

The offensive is a tremendous gamble by Giap and is undertaken as a result of U.S. troop withdrawal, the strength of the anti-war movement in America likely preventing a U.S. retaliatory response, and the poor performance of South Vietnam's Army during Operation Lam Son 719 in 1971.

North Vietnamese Army troops, artillery and tanks rolled into South Vietnam. South Vietnamese divisions backed up by firepower from U.S. planes including B-52 bombers slowed down then halted the offensive. It was a huge miscalculation by the North and it cost them dearly with North Vietnamese Army casualties eventually exceeding 100,000 with at least half of their large caliber artillery and tanks lost as well.

On April 2, airstrikes against the North Vietnamese attack were authorized under the name Freedom Train. At first, these strikes were in support of the South Vietnamese forces, but later the restrictions against attacking North Vietnam were lifted and the effort changed to that of the interdiction of supply lines. The first of these raids against the North was a raid by 15 B-52Ds on railway yards and oil storage facilities at Vinh.

Three days later, the airfields at Bai Thuong were hit. On the weekend of 15-16 April, targets near Hanoi and Haiphong were attacked. By mid-April, virtually all of North Vietnam had been cleared for bombing raids, for the first time in more than 3 years. On May 10, the name of the operation against North Vietnam was changed to Linebacker.

In the meantime, negotiations were underway in Paris between National Security Advisor Henry Kissinger and North Vietnamese leader Le Duc Tho, trying to establish some sort of framework under which the US could withdraw from an increasingly unpopular war and still leave some sort of military parity between North and South Vietnam.

On October 23, progress in the peace talks in Paris led the US to call off all air operations above the 20th parallel, which put Hanoi and Haiphong off-limits. This effectively halted Linebacker. Unfortunately, this gave the North Vietnamese a breathing spell in order to strengthen their defenses and repair the damage to their key lines of communication.