For many critics, President Reagan touched a nerve when, on March 23, 1983, he called on Western technology to ''counter the awesome Soviet missile threat with measures that are defensive.'' Immediately dubbed ''star wars,'' the President's Strategic Defense Initiative (SDI) has been embroiled in inflated rhetoric that is obscuring what should be a fundamental reconsideration of US strategic policy.
The threat of nuclear retaliation has long provided the basis of US deterrence policy. But growth in Soviet power has today placed the United States in a position some characterize as one of strategic parity, others as one of US inferiority. In either case, the dangers of relying on offensive nuclear deterrence have increased, and the credibility of American nuclear retaliation in response to Soviet aggression has declined. Faced with this dilemma, we are unable to agree on a program for offensive modernization (witness the MX debate) , much less a coherent nuclear strategy. At the same time the advance of technology - notably computers, sensors, and microelectronics - is making the survivability of our offensive forces appear increasingly doubtful.
The SDI research program is based on the expectation that the technologies jeopardizing our present deterrent may suggest alternative means to ensure Western security. It provides a timely and prudent alternative to the offensive nuclear competition in which the US so reluctantly engages. Technical and political objections to strategic defense ought to be taken seriously, but should not preclude a thorough analysis of the possible value of defensive systems in the future strategic environment:
1. Defense must be perfect, but perfection is not possible. The development of leakproof defenses will indeed likely prove impossible. But less-than-perfect defenses could provide critical assets that form the core of the US deterrent - offensive nuclear forces, US-based conventional forces, key industrial facilities, command-and-control systems - enough protection to destroy confidence in any attack plan, leaving the Soviets little incentive to use nuclear weapons against the US. The US population, while still vulnerable to a direct attack, would receive indirect protection, because the American deterrent would be strengthened.
2. The technology for strategic defenses will not work. The SDI is pursuing research on a variety of technologies for the components of a defensive system. It is not possible at this time to assert responsibly which technologies could, or could not, be assembled to actually meet the conditions for future deployment.
3. Offensive nuclear forces will always be more cost effective than defenses. There is no reason to believe that this conventional wisdom of the 1960s is a law of nature. Depending on their characteristics and deployment, strategic defenses can have considerable leverage over offenses. In addition, one of the functions of research and development, and a major goal of the SDI, is to minimize deployment costs.
4. Defense is destabilizing - i.e., it increases the likelihood of war. Actually, the technical improvement of offensive nuclear forces is increasing the incentive to preempt in a crisis. The Soviets now threaten a significant and growing portion of US land-based ICBMs and bombers. The possibility of a Soviet breakthrough in submarine detection, putting at risk our ballistic missile submarines, cannot be discounted. Even absent such a breakthrough, reliance on only the submarine leg of the triad, shrinking in numbers and hampered by poor communications, would leave little chance to terminate a conflict on any terms short of mutual annihilation.
In short, there are good reasons for the US to reexamine its existing dependence on offensive-only nuclear deterrence. In doing so, one might consider other options besides strategic defense, including reducing overseas commitments drastically in order to remove the most demanding requirements on our strategic forces.
But in facing this necessary decision, the US should not automatically and dogmatically dismiss the option of strategic defense. We must recognize that the ''long twilight struggle'' foreseen by President Kennedy will continue so long as US and Soviet objectives remain fundamentally incompatible. We should pursue that struggle on paths that take advantage of our strengths and are most likely to ensure Western survival.Roy Pollock is a visiting scholar and Patrick J. Garrity is a fellow at the Center for Strategic and International Studies, Georgetown University.