Deterrence is once again a topic of discussion and debate among US defense and policy communities. Although the concept has received comparatively little attention since the end of the Cold War, it seems poised to take center stage in America's national security policy during the coming decades. Adversary-specific deterrence strategies will likely become prominent in national and international security decisions for an increasingly multipolar world, with two wars already straining the military, concerns about a recalcitrant and militarized Russia, Iran's continued uranium enrichment activities, North Korea's nascent nuclear arsenal, and top-to-bottom military modernization in China.
As part of this renewed interest in deterrence, conventional weapons are playing an important role. The "New Triad," consisting of both nuclear and advanced conventional weapons; proposals for conventionally armed intercontinental ballistic missiles; and, more generally, the concept of Prompt Global Strike all represent a growing belief that advanced conventional capabilities can substitute for some missions previously relegated solely to nuclear weapons. Although there has been considerable debate over these specific initiatives--for example, the effect that putting conventional warheads on ballistic missiles would have on strategic stability-most specialists agree that conventional forces can help reduce the role of nuclear weapons in US security strategy. In fact, in recent years the US military has expanded the concept of "strategic deterrence," a term that once encompassed only intercontinental nuclear weapons, to incorporate both nuclear and conventional forces, as well as diplomatic, economic, and informational tools. (1)
The recent emphasis on substituting conventional for nuclear weapons in selected missions is an important step in developing a credible and robust twenty-first century deterrent, but it does not fully consider the unique logic and strategy of conventional deterrence. The current debate focuses primarily on the use of conventional weapons for "deterrence by punishment," the threat to impose unacceptable costs, such as the destruction of an adversary's strategic and high-value targets, in response to unwanted actions. Yet, one of the most important contributions of conventional forces is "deterrence by denial," the threat to deny an adversary the ability to achieve its military and political objectives through aggression. (2) If early strategists were accused of "conventionalization" by treating nuclear weapons merely as more powerful and effective tools of war, the current debate regarding conventional contributions to deterrence may be accused of "nuclearization," in that it treats conventional capabilities merely as a substitute for nuclear weapons.
The following assessment has the purpose of expanding the discussion related to the role and utility of conventional forces in US strategies by reexamining the traditional logic of conventional deterrence. That logic focuses primarily on deterrence by denial, in the context of the modern international security environment. It is primarily concerned with the role of US conventional forces in extended deterrence, defined as the threat of force to protect allies and friends, rather than "central" or "homeland" deterrence. (3) This focus on extended deterrence, and especially on the role of deterrence by denial, highlights the importance of protecting territory from attack and invasion. Historically, the desire for control over specific territory has been a frequent motivator of interstate crises and conflict. (4) While interstate conventional wars have significantly declined since the end of the Second World War, the potential for conflict over Taiwan or on the Korean Peninsula, the prospect of future clashes over control of scarce natural resources, and the 2008 war between Georgia and Russia attest to the continued possibility of conflict over specific territory that has important strategic, economic, political, religious, historical, or socio-cultural significance. …