The Strategic Defense Initiative

The Strategic Defense Initiative (SDI) was a major program for defense against Soviet missiles championed by President Ronald Reagan beginning in 1983.

The U.S. missile defense program began in March 1946 in response to Germany's World War II missile program that included plans for an intercontinental ballistic missile (ICBM). By the mid‐1950s, when intelligence indicated the Soviets were developing their own ICBM, both the army and air force were pursuing missile defense programs. In 1958, to end squabbling that had developed between the two services, the secretary of defense assigned responsibility for missile defenses to the army.

After its Nike Zeus missile achieved the first successful intercept of a dummy ICBM warhead in July 1962, the army pushed for the deployment of national missile defenses. Secretary of Defense Robert S. McNamara successfully resisted such a deployment until September 1967. By then, the Soviets were deploying their own system around Moscow; in response, President Lyndon B. Johnson ordered the fielding of Sentinel to provide limited protection for U.S. cities.

Following his election in 1968, President Richard M. Nixon switched the focus of Sentinel to defense of deterrent forces and renamed it Safeguard. In August 1969, about two months after Nixon had invited the Soviets to discuss reductions in strategic arms, Congress approved the Safeguard deployment.

The first phase of the Strategic Arms Limitation Talks (SALT) produced the Anti‐Ballistic Missile Treaty in May 1972. It restricted the signatories to two missile defense sites, each having up to one hundred interceptors. A 1974 protocol reduced to one the number of sites each nation could deploy.

About a year after the protocol, the United States completed its Safeguard site at Grand Forks, North Dakota. A few months later, Congress ordered the Department of Defense (DoD) to close the facility. The Soviet missile defense system near Moscow remains operational.

After the closure of Safeguard, the army concentrated its missile defense efforts on developing hit‐to‐kill (HTK) missiles to replace the nuclear‐tipped interceptors required by Safeguard. In June 1984, this new interceptor concept was successfully demonstrated.

In the meantime, the Soviets were improving their nuclear forces. By the early 1980s, some strategic analyses showed the Soviets could cripple U.S. retaliatory forces and still have enough missiles to devastate American cities. As a result, in a February 1983 meeting with President Reagan, the Joint Chiefs of Staff (JCS) recommended greater emphasis on strategic defenses.

Already supportive of missile defenses, Reagan was receptive to this message. In a nationally televised speech on 23 March 1983, he announced his decision to initiate an expanded research and development program to assess the feasibility of strategic defenses. In April 1984, following a year of technical and strategic studies, DoD chartered the Strategic Defense Initiative Organization under the leadership of Air Force Lt. Gen. James A. Abrahamson. This organization was to conduct the research to resolve the feasibility issue.

After two and a half years of work, the president and Secretary of Defense Caspar Weinberger decided at the end of 1986 to enter the Strategic Defense System (SDS) Phase I Architecture into the defense acquisition process. This architecture had two major deficiencies: it was expensive, and its space‐based elements were vulnerable to Soviet antisatellite weapons (ASATs). These difficulties were epitomized in the space‐based interceptor (SBI), one of the architecture's six subsystems.

SBI was a large, garagelike satellite housing ten hit‐to‐kill interceptors. About 300 SBIs were to orbit the Earth. In case of a Soviet attack, the SBIs would launch their interceptors at Soviet missiles, destroying many of them before they could release their multiple warheads and decoys. Because of its complexity, SBI was costly; because of its size, it was an easy target for ASATs.

The solution to these problems was to use miniaturized sensors and computers to give individual interceptors the ability to operate without support from a garage. Instead of several hundred large targets, Soviet ASATs would now confront several thousand small, hard‐to‐find interceptors. Because these Brilliant Pebble interceptors (BP) were to be mass‐produced, they would be relatively inexpensive, thereby lowering the cost of SDS Phase I.

The decision to integrate BP into the architecture came in 1989, as the Soviet empire began to crumble. This dramatically changed the strategic situation, prompting President George Bush to initiate a review of U.S. strategic requirements. The SDI portion of this review was completed in March 1990 by Ambassador Henry Cooper, who had served as America's chief negotiator during the defense and space talks. Cooper's report argued that the most dangerous threat to the United States was now unauthorized or terrorist attacks by limited numbers of missiles. Moreover, deployed U.S. forces would increasingly face threats from shorter‐range theater missiles as the technology of ballistic missiles and weapons of mass destruction proliferated. Cooper recommended refocusing SDI to concentrate on defenses against these new threats.

Shortly after Cooper took over the SDI organization, his report proved prophetic. In August 1990, Iraq invaded Kuwait, touching off a crisis that led to the Persian Gulf War of 1991. This war produced the first operational engagement between a ballistic missile (an Iraqi Scud) and a missile defense system (the American Patriot). Furthermore, the danger of theater missiles was graphically illustrated on 25 February when a single Scud killed twenty‐eight Americans and injured one hundred.

Responding to the new world situation, on 29 January 1991, President Bush had announced a reorientation of the SDI program away from developing strategic defenses to a new system known as GPALS for Global Protection Against Limited Strikes. GPALS consisted of three main components: a ground‐based national missile defense (NMD), a ground‐based theater missile defense (TMD), and a space‐based global defense. In this scheme, the space‐based element complemented TMD and NMD.

The emphasis on TMD reflected in GPALS was reinforced under President Bill Clinton, whose secretary of defense, Les Aspin, Jr., changed the name of the Strategic Defense Initiative Organization to the Ballistic Missile Defense Organization. In announcing this change on 13 May 1993, Aspin hailed the end of the Cold War and credited SDI with helping to end it.

In September 1993, a new shape for America's missile defense program emerged from the Bottom‐Up Review (BUR), the Clinton administration's study of America's post–Cold War defense needs. The BUR laid out a three‐part, $18 billion missile defense program covering the six years of the future years defense plan. The top priority was to be a $12 billion TMD component focused on three programs: improvements to the Patriot missile system; upgrading the navy's Aegis air defense system so it could intercept theater ballistic missiles; and a new army system known as Theater High Altitude Area Defense to complement Patriot. The second element of the plan was a $3 billion “technology readiness” program to shorten NMD's deployment time. Finally, a $3 billion technology program was to support both national and theater defenses.

Over the next few years, the Clinton administration would find it necessary to expand the TMD program and increase its funding. Additional funding was also required for NMD, which had to be transformed into a deployment readiness program to permit rapid fielding of defenses as the missile threats to the U.S. homeland suddenly emerge. Nevertheless, the BUR had provided the broad framework that guided the U.S. missile defense program into the new millennium.
[See also Air and Space Defense; Arms Control and Disarmament: Nuclear; Deterrence; SALT Treaties; Space Program, Military Involvement in the; Weapons, Evolution of.]

Bibliography

B. Bruce‐Briggs , The Shield of Faith: A Chronicle of Strategic Defense from Zeppelins to Star Wars, 1988.
Donald R. Baucom , The Origins of SDI, 1944–1983, 1992.
David B. H. Denoon , Ballistic Missile Defense in the Post–Cold War Era, 1995.

Donald R. Baucom