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US Defenses Against ICBMs, 1958-1976

From Nike-Zeus to Safeguard: US Defenses Against ICBMs, 1958-1976

Nike-Zeus and Nike-X (1958-1965)

During the late 1950s and early 1960s the development of Soviet ICBMs focused attention in the United States away from air defense and onto ways to protect the country against ballistic missile attack. In 1958 the Army received approval to develop the Nike-Zeus anti-ballistic missile. The Nike-Zeus was a long-range interceptor missile with a nuclear warhead that was designed to destroy incoming warheads above the atmosphere. The interceptor was intended to maneuver close to the attacking missile warhead and destroy it with a nuclear blast.

The Army proposed rapid deployment of the system but critics from the White House, Office of the Secretary of Defense, and Air Force resisted, arguing the system was too primitive to handle the real Soviet threat. The Nike-Zeus system's radars were mechanically steered, meaning that they would be overwhelmed by a large attack, and were also vulnerable to blinding or destruction. The high cost of fully deploying the system and the fear that the Soviet Union might respond by increasing its offensive forces, as well as the fact that it could be defeated by countermeasures such as chaff or decoys, led policy-makers to deem Nike-Zeus too ineffective to deploy.

In 1963, the Nike-X program replaced Nike-Zeus. Nike-X added a new, electronically steered phased-array radar, which allowed the system to track many targets at once. It included a new short-range interceptor, called Sprint, which also used a nuclear warhead but was designed to intercept incoming warheads within the atmosphere. In addition, the long-range Nike-Zeus interceptor was eventually upgraded to become the Spartan. Even as the system was being improved, however, the controversy over the technical and strategic problems associated with missile defenses continued.


Sentinel (1966-1968)

In 1966 pressure was growing for deployment of a US ABM system, partly based on the knowledge that the Soviet Union was moving ahead with its planned missile defense to protect Moscow. President Lyndon Johnson included several hundred million dollars for such a program in the 1967 budget, but at the suggestion of Secretary of Defense Robert McNamara, decided to withhold the money until an attempt had been made to negotiate an ABM agreement with the Soviets. When negotiations failed, Johnson decided to go ahead with the construction of a "thin" ABM system, called Sentinel, based on Nike-X technology and intended to protect US cities from a limited nuclear attack.

McNamara announced the decision in a speech in September 1967, arguing against a "thick" ABM system on the grounds that it was not possible to completely protect the United States from missile attacks and that trying would only accelerate the arms race with the Soviet Union. Instead, he said, the United States would deploy a "thin" ABM system to provide protection against smaller-scale threats, such as that posed by Chinese missiles. The announcement was greeted with widespread criticism from scientists and Congress, and also provoked large-scale public protests when it became clear that the nuclear-tipped interceptor missiles would be deployed very close to the cities they were meant to defend. Skeptics also pointed to the fact that domestic politics was likely playing a role since it was an election year, and the administration was bound to be attacked by the Republicans if it did not act.


Safeguard (1969-1976)

When Richard Nixon came into office in 1969, he decided Johnson's idea of a thin ABM system was good, but the mission was wrong. The Nixon administration instead proposed the Safeguard system, with the objective of protecting only crucial military sites. The system was never intended to provide more than minimal protection for the general public, and that only in a small area. Under the Safeguard program, the United States would deploy long- and short-range ABM missiles at up to twelve sites to provide a limited defense of Minuteman ICBM fields, Strategic Air Command bases, and the National Command Authority in Washington, D.C.

The Senate approved the Phase I deployment of Safeguard by a 50-50 vote, with Vice President Spiro Agnew breaking the tie, in August 1969. Whether the system would work was only one element of the decision. Part of the reasoning behind the approval was that the United States would need the system as a bargaining chip in the upcoming SALT talks with the Soviet Union. There were also political considerations at work -- Senators did not want to seem weak on defense to either their constituents or defense contractors.

The original twelve possible Safeguard sites were reduced to two during ABM Treaty negotiations with the Soviet Union in 1972. For the United States, these sites were Grand Forks Air Force Base, North Dakota and Washington, D.C. In 1974, both countries signed a Protocol to the treaty reducing the permitted number of sites from two to one, with a total of one hundred interceptors. In the end, Grand Forks was the only US site ever built; it became operational on October 1, 1975.

On October 2, 1975 -- one day after the site became operational -- the House voted to inactivate Safeguard. The House decision was based on the argument that the restriction to a single ABM site combined with the recent Soviet development of MIRVs meant the system could not handle the threat. Soviet missiles with multiple warheads would overwhelm the system. This was not the only problem, however. The radars that tracked incoming missiles were extremely vulnerable: they would black out when a nuclear warhead -- including one on a US interceptor missile -- detonated. Once the radars were destroyed, the system would be electronically blind and therefore useless. Safeguard's ability to achieve even its main objective of protecting the North Dakota ICBM site was also limited by the fact that its 100 interceptor missiles were not enough to counter a determined attack.

In fact, the DOD had already reached the same conclusion and had decided in 1974 to shut down the Grand Forks site on July 1, 1976. Although the Senate initially rejected the House position, and approved Safeguard funding, once the DOD's decision was brought to their attention, they agreed to terminate the program. The bill the Senate passed in November 1975 allowed operation and testing of the site's perimeter acquisition radar but closed down the remainder of Safeguard.

It took several months for the Army to begin shutting down Safeguard, but in February 1976 -- five months after it became operational--the site was placed in caretaker status. The total cost of the Safeguard project was $5 billion -- $23 billion in current (FY-99) dollars.

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