US-Russian disagreements over the proposed deployment of land-based missile defenses in Poland and Czech Republic have renewed the debate over the impact of defenses on arms control. In an article posted on the Centre for Research on Globalization web site, former US intelligence and arms control official Scott Ritter asserted, "If the members of the Obama administration would bother to take a stroll down memory lane, they might recall that once upon a time there was a document called the anti-ballistic missile treaty, signed in 1972 between the United States and the former Soviet Union, which recognized that anti-missile defense shields were inherently destabilizing, and as such should not be deployed." Ritter's statement bears closer scrutiny.

During the Cold War the Soviets deployed the world's only active ballistic missile defense system. Today, Moscow is still protected by a Missile Defense System. This system never played a relevant role in destabilizing competition between the super powers. Additionally, although the issue remains hotly debated, some scholars (see, for example, William Odom, The Collapse of the Soviet Military) contend that the proposal to develop the Strategic Defense Initiative by US President Ronald Reagan accelerated arms control agreements with the Soviet Union.

Research at The Heritage Foundation employing game theory also suggests that missile defense, rather than being destabilizing, actually contributes to limiting the likelihood of nuclear confrontation. Heritage analyst Baker Spring developed a game theory application that studied the affects of missile defense on nuclear competition in a "proliferated" environment where several countries (with independent foreign policies) had access to ballistic missiles and nuclear weapons. According to Spring the outcome of his research suggests that "the presence of defenses in a multi-player setting not only does not feed instability, but also may contribute to stability."

First, the outcome of the games generally showed that the more widespread the presence of defenses, the lower was the propensity to ready offensive (nuclear) arms and fire shots with these arms. It also showed a greater propensity to aban¬don offensive arms (disarm) as defenses became more widespread.

Second, the more widespread the presence of defenses, the lower the propensity to adopt hos¬tile attitudes toward one another or move to threaten each other.

Third, the more widespread the defenses, the less likely an aggressive actor's conclusions favored aggressive actions.

For full results of the nuclear games, see Nuclear Stability Working Group, Nuclear Games: An Exercise Examining Stability and Defenses in a Proliferated World (Washington, D.C.: The Heritage Foundation, 2005), at www.heritage.org/upload/NuclearGames.pdf.