The air campaign mounted against North Vietnam between 1965 and 1972 was the first time that an integrated air defense system based around radar-controlled guns and surface-to-air missiles had been encountered. Proponents of surface-to-air missiles had claimed that their lethality would drive manned aircraft from the battlefield.
The U.S. Air Force was hard-pressed to neutralize North Vietnam's radar-controlled defenses, but did prevail and successfully delivered punishing blows during Operation Linebacker II in December 1972.
Electronic countermeasures support for the air war against North Vietnam included stand-off jamming, Wild Weasel operations, the use of self-protection pods, and the employment of chaff. Using all these techniques, Linebacker II saw the B-52s of Strategic Air Command facing the most effective air defense system the Soviet Union could provide. The B-52s won; the much-heralded surface-to-air missiles were scoring a lower kill rate than German defenses in World War Two