y the early to mid-1980s, the United States will be unable to repose confidence in the ability of all save a small fraction of its silo-housed missile force to ride out a Soviet first nuclear strike. The possible implications of this early predictable development, and the policy choices that it poses for the U.S. government, are the subjects of this article. For nearly 20 years the United States has maintained a triad of strategic forces, comprising silo-housed intercontinental ballistic missiles (ICBMs), submarine-launched ballistic missiles (SLBMs), and manned penetrating bombers. An entire leg of this triad is approaching mass obsolescence ? as currently deployed in fixed hardened sites. Although the growing debate over the meaning of silo vulnerability is focused heavily upon the issue of whether or not a follow-on ICBM, called MX (missile experimental), should be developed and procured ?and if so, how it should be de ployed?the MX debate is operating as a catalyst to open, or reopen, discussion of a wide-ranging set of strategic and political issues. At stake in, and closely related to, the MX/ICBM debate are matters of far deeper significance than might immediately be discerned. At one level, it is the technical merits of a particular weapon system, in all aspects, that are being debated ?but behind the technical issues lurk such questions as the following: What will the United States ask of its strategic forces in the 1980s and 1990s (i.e., what quantity and quality of strategic posture will be appro priately supportive of American foreign policy)? How do we deter the Soviet Union in plausible (or not implausible) crises and conflicts in the 1980s and 1990s? How do the strategic forces contribute to that deterrence? To a major degree, technical answers must be driven by broad political-military choice. Our foreign policy goals, be they more or less expansive than in the past, should point to a prudent strategic