Anti-Ballistic Missile Treaty - Background

Background

Throughout the late 1950s and into the 1960s, the United States and the Soviet Union had been developing a series of missile systems with the ability to shoot down incoming ICBM warheads. During this period the US considered the defense of the US as a part of reducing the overall damage inflicted in a full nuclear exchange. As part of this defense, Canada and the US established the North American Air Defense Command (now called North American Aerospace Defense Command NORAD).

By the early 1960s, US research on the Nike Zeus missile system had developed to the point where small improvements would allow it to be used as the basis of a "real" ABM system. Work started on a short-range, high-speed counterpart known as the Sprint to provide defense for the ABM sites themselves. By the mid-1960s, both systems showed enough promise to start development of base selection for a limited ABM system dubbed Sentinel. However, due to political debate, Sentinel never expanded beyond defense of missile-bases.

An intense debate broke out in public over the merits of such a system. A number of serious concerns about the technical abilities of the system came to light, many of which reached popular magazines such as Scientific American. This was based on lack of intelligence information and reflected the American nuclear warfare theory and military doctrines. The Soviet doctrine called for development of their own ABM system and return to strategic parity with the US. This was achieved with the operational deployment of the A-35 ABM system and its successors, which remain operational to this day.

As this debate continued, a new development in ICBM technology essentially rendered the points moot. This was the deployment of the Multiple Independently targetable Reentry Vehicle (MIRV) system, allowing a single ICBM to deliver as many as ten separate warheads at a time. This way, any ABM defense system could be overwhelmed with the sheer numbers of warheads. Upgrading it to counter the additional warheads would be economically infeasible—the defenders required one rocket per incoming warhead, whereas the attackers could place 10 warheads on a single missile at a reasonable cost. To further protect against ABM systems, the Soviet MIRV missiles were equipped with electronic countermeasures and heavy decoys. R-36M heavy missiles were carrying as many as 40 of them. These decoys would appear as warheads to ABM, effectively requiring engagement of 50 times more targets than before and rendering defense even less effective.

At about the same time, the USSR reached strategic parity with the US in terms of ICBM forces. A nuclear war would no longer be a favorable exchange for the US, as both countries would be devastated. This led in the West to the concept of mutually assured destruction, MAD, in which any changes to the strategic balance had to be carefully weighed. To the U.S., ABMs now seemed far too risky—it was better to have no defense than one that might trigger a war.