AIR DEFENSE. Although American cities were not in danger of attack by air during World War I (1914–1918), American military planners did not overlook the ordeal of Great Britain under such attacks. Remote as the possibility was of bombing raids against the United States during the interwar period, war studies contemplated guarding against them through the use of fighter aircraft, antiaircraft artillery (AAA), and ground observers. In 1935, the United States War Department established regional air defense systems, incorporating radar by the end of the decade. By 7 December 1941, air defense systems—including radar, fighters, AAA, ground observers, and control centers—had been established along both continental coasts, in Panama, and in Hawaii. After the Japanese attack on Pearl Harbor, and the failure of the base's primitive radar system, air defense nationwide was greatly expanded. However, by 1943 it was evident that neither Germany nor Japan was capable of inflicting serious damage on American cities, so the air defenses were demobilized by the war's end.
After World War II (1939–1945), the tensions of the Cold War stimulated rapid development of air defenses throughout the continental United States, beginning with the 1946 establishment of the Air Defense Command (renamed Aerospace Defense Command in 1968). By 1950, construction of an improved radar network had begun, and several hundred modern radar stations would blanket the country a decade later. Until the electronic network came into full operation, a Ground Observer Corps of about 500,000 civilian volunteers provided backup warning capability. Radar surveillance extended northward into Canada, as well as seaward, by way of patrol ships and radar platforms. Intensive research and development in the application of electronic computers to air defense culminated in the early 1960s in the deployment of about twenty Semi-Automatic Ground Environment (SAGE) computerized combat operation centers networked throughout the country. In 1958, the United States and Canada pooled their air defense resources for the common defense of their territories and established the North American Air Defense Command (NORAD). NORAD headquarters was established in a cavern under Cheyenne Mountain near Colorado Springs, Colorado.
With the coming of the space age, the world powers focused on developing inter-continental ballistic missiles (ICBMs). To counter this new threat, a Ballistic Missile Early Warning System was established, with special radar stations in Alaska, Greenland, and the United Kingdom. By The early 1960s, the ICBM had replaced the manned bomber as the chief instrument of intercontinental air warfare. Consequently, air defense priorities were readjusted to meet the new threat. In the early days of anti-ICBM defense, the system relied on the deterrent of over-whelming ICBM retaliation in the event of an attack—a concept known as "mutually assured destruction." The 1970s saw the construction of a Ballistic Missile Defense System, code-named "Safeguard." The system included radar, short-and long-range missiles, and supporting automatic data-processing equipment. Original plans called for large-scale deployment throughout the United States; but the Strategic Arms Limitation Talks (SALT I) between the United States and the Soviet Union resulted in a treaty, ratified by the U.S. Senate in July 1972, limiting each country to only two antiballistic missile (ABM) defenses. The United States constructed only one Safeguard missile site, in North Dakota, in 1974.
In March 1983, President Ronald Reagan called for the Strategic Defense Initiative (SDI), an advanced ground-and-space-based anti-ballistic missile system that would change the nature of the Cold War and hasten the demise of the Soviet Union. Western critics charged that SDI was too complex and expensive, but to Reagan, that was the whole idea. He foresaw that the Soviets could not compete with the United States in the race for SDI, not only with the vast amounts of money required for re-search and development, but also with the cutting-edge technology required. Even as American critics mocked the potential of SDI, attempting to trivialize it with the derisive name "Star Wars," the Soviets themselves gave the greatest credence to it by actually walking out of the October 1986 summit in Reykjavik, Iceland, when President Reagan refused their demands to give it up. Rejecting the doctrine of mutually assured destruction, President Reagan even offered to share SDI, when completed, with the Soviets. While research on SDI continued into the twenty-first century, and the system remained undeployed, it is recognized as a turning point not only in the technology of air defense, but in the Cold War that it helped to end with Western victory.
The Persian Gulf War (1991) saw the use of the Patriot Air-Defense Missile. Placed around Allied troop bivouacs, ports, and airbases in the Persian Gulf region, the fully automated Patriot tracked incoming Iraqi SCUD missiles with sophisticated radar, giving roughly six minutes of warning and launching automatically when the probability of an interception and kill was highest.
The Patriot system was originally intended as an anti-aircraft defense, but the needs of the war led the Army to improvise its new anti-missile role. While the military and White House hailed it as a success, critics claimed the effectiveness of the Patriot was overrated. Overall the system served as a valuable asset, not only militarily, but also politically, in reassuring Israel of American protection from Iraqi attacks.
The terrorist attacks on the United States that occurred on 11 September 2001 brought the difficulties of air defense to national attention once again. While the unconventional nature of the attacks made them difficult to counter, the tragedies certainly illuminated the ongoing desire for, as well as the complexities of, what General Dwight D. Eisenhower described in 1946 as a weapon that could "hit a bullet with another bullet."
Atkinson, Rick. Crusade: The Untold Story of the Persian Gulf War. Boston: Houghton Mifflin, 1993.
Boyne, Walter J. Beyond the Wild Blue: A History of the U.S. Air Force, 1947–1997. New York: St. Martin's Press, 1997.
Goldberg, Alfred, ed. A History of the United States Air Force, 1907–1957. Princeton, N.J.: Van Nostrand, 1957.
Leyden, Andrew. Gulf War Debriefing Book: An After Action Report. Grants Pass, Oreg.: Hellgate Press, 1997.
Christian MarkDe John