South Vietnam: The Easter Offensive: Communist Gamble, 1972

South Vietnam: The Easter Offensive
With the majority of U.S. troops out of South Vietnam, the North Vietnamese sensed an opportunity to end the war with a conventional invasion. On March 30, 1972, North Vietnam launched the Easter Offensive — a large, three-pronged drive into South Vietnam using heavy tanks and mobile units. U.S. airpower played an essential role in stopping the attack. The biggest battle occurred during the North Vietnamese siege of An Loc. Airpower not only supplied materiel to the encircled ground forces, but also destroyed nearly all of the North Vietnamese tanks and artillery.  DOD feature compilation, photos.

When the Easter Offensive came to a halt, however, North Vietnam controlled much of South Vietnam near the Demilitarized Zone (DMZ), along with a strip of land along South Vietnam’s border with Laos and Cambodia.

North Vietnam: Linebacker and Linebacker II: Wild Weasels and Linebacker Operations: The War Ends
GOING DOWNTOWN

In response to the North Vietnamese “Easter Offensive” into South Vietnam in 1972, President Nixon suspended peace talks on May 8 and ordered OPERATION LINEBACKER, the renewed bombings of North Vietnam and the aerial mining of its harbors and rivers. When North Vietnam seemed ready to talk peace in October, Nixon directed yet another bombing halt. North Vietnam then balked for two months over cease-fire provisions. So, Nixon eliminated the sanctuaries and ordered the heaviest bombing of the entire war against Hanoi and Haiphong, OPERATION LINEBACKER II.

Operations Linebacker and Linebacker II initiated the end of the Southeast Asia War. During those offensives, U.S. airpower stopped the North Vietnamese ground offensive and B-52s vigorously bombed previously untouched targets in North Vietnam. The Wild Weasels challenged North Vietnamese defenses that had been heavily built up over the course of three and a half years. 

In the spring of 1972 the U.S. renewed large-scale bombing of North Vietnam in response to the communist Easter Offensive against South Vietnam. Since the end of Rolling Thunder in 1968, the North Vietnamese had developed their fighter forces and created an integrated defense system of mutually supporting early warning radar, AAA and SAM sites. By 1972 the North Vietnamese had more than 200 SA-2 launchers, extending their coverage into parts of South Vietnam. 

To assist the 17th Wild Weasel Squadron, the USAF sent over part of the F-105G-equipped 561st Tactical Fighter Squadron — together they totaled 28 F-105 Wild Weasel aircraft. In addition to these, the USAF introduced the F-4C Wild Weasel IV to combat during Linebacker. 

Efforts to make the F-4C a Wild Weasel aircraft started in 1966, but developmental problems prevented it from being fielded until the spring of 1969. One F-4C Wild Weasel unit, the 67th TFS at Kadena Air Base, Okinawa, sent six F-4C Wild Weasels to Korat, Thailand, in September 1972. Used in southern North Vietnam during Linebacker, the F-4C Wild Weasel aircrews effectively supported strikes around Hanoi during Linebacker II, flying 460 sorties in Southeast Asia without loss. 

Linebacker II, the most concentrated air campaign against North Vietnam, began on Dec. 18, 1972, after the communists again stalled at the peace table. Over half the targets were within 25 miles of Hanoi, protected by some of the densest air defenses in the world. Even so, the Wild Weasels, along with other anti-SAM measures, kept SA-2 losses relatively low, without any losses to themselves. In 1972, the year of Linebacker and Linebacker II, the North Vietnamese fired over 4,000 SA-2s — nearly half the total they fired during the entire war — shooting down 49 U.S. aircraft (meaning it took over 80 SA-2s to down one aircraft). 

Beginning on Dec. 18, the USAF pounded military and transportation targets with B-52s and tactical fighters. After 11 days of intense bombing, the North Vietnamese finally agreed to return to the peace table in Paris. Consequently, the U.S. restricted its air attacks on North Vietnam to the area south of the 20th parallel.

On Jan. 15, 1973, the U.S. announced an end to all mining, bombing and other offensive operations against North Vietnam. A peace agreement, initialed on Jan. 23 and officially signed on Jan. 27, took effect on Jan. 28. The communists agreed to a cease-fire and to peaceful reconciliation and reunification with South Vietnam, and the agreement brought an end to U.S. combat operations over North Vietnam. 

Sidebar: Getting Closer: Precision Guided Weapons in the Southeast Asia War

Despite early developmental problems, precision guided munitions (PGM) revolutionized the air war in Southeast Asia. By the war’s end, laser guidance kits turned standard bombs into “smart bombs,” making them 100 times more effective than free-fall, unguided bombs.

At first, the U.S. Air Force’s conventional bombs lacked the accuracy to destroy tough targets like the Thanh Hoa Bridge (or “Dragon’s Jaw” Bridge), 70 miles south of Hanoi. In April 1965 radio-guided Martin AGM-12 Bullpup missiles were used on the first attack on the bridge. With just a 250-pound warhead, they proved too lightweight to do any real damage. Repeated air attacks failed to destroy this important bridge completely until very late in the war.

The U.S. Air Force tried the electro-optically guided Rockwell International GBU-8 and the Martin Marietta AGM-62 Walleye, but these PGMs had trouble distinguishing the target, were too expensive or still too small for hardened targets like the Dragon’s Jaw Bridge.

A revolution in PGM development occurred when Col. Joseph Davis Jr., at the Air Proving Ground at Eglin Air Force Base, Fla., and Weldon Word, an engineer with Texas Instruments, adapted the U.S. Army’s laser guidance systems to work on bombs. In 1968 the U.S. Air Force evaluated in combat the world’s first laser-guided bomb (LGB), the Texas Instruments BOLT-117. Despite its good results, the U.S. Air Force adopted the more powerful Texas Instruments GBU-10 Paveway I, a conventional 2,000-pound MK 84 bomb adapted with a laser guidance system. The resulting accuracy was impressive with almost half of all LGBs dropped in Southeast Asia hitting their target. Most of the other LGBs hit within 25 feet.

In April 1972 the U.S. Air Force used LGBs to destroy the Dragon’s Jaw Bridge and the more famous Paul Doumer Bridge just outside of Hanoi. During the last year of the war, LGBs destroyed 100 more bridges across North Vietnam.