Air power refers to the use of aviation by nations and other political actors in the pursuit of power and security interests, along with the use of long-range missiles. Since armies and navies first began to experiment with the use of airplanes as implements of war, air power has emerged as an integral component of modern warfare. Air power was born in the crucible of World War I, but came of age in the conflagration of World War II. The developmental history of air power is significant to security studies in general and to the study of air power in particular. Owing to the rapid series of state changes in air power, trying to understand the nature of air power and its effects on modern warfare and international security has become more complicated. Two questions that are central to the study of international security are whether air power facilitates offense as a whole and whether it encourages aggression as a result. There has also been a debate over the issue of how air power can most effectively be used to coerce an enemy through strategic bombing. Another source of disagreement is the question of whether air and space power constitute one subject or two. In general, there are compelling merits in treating space power as a domain of national security theory and policy separate from those of land, sea, and air power.
Karl P. Mueller
Stephen M. Walt
Political Realism has been described as the “oldest theory” of international politics, as well as the “dominant” one. Central to the realist tradition is the concept of “security.” Realism sees the insecurity of states as the main problem in international relations. It depicts the international system as a realm where “self-help” is the primary motivation; states must provide security for themselves because no other agency or actor can be counted on to do so. However, realists offer different explanations for why security is scarce, emphasizing a range of underlying mechanisms and causal factors such as man’s innate desire for power; conflicts of interest that arise between states possessing different resource endowments, economic systems, and political orders; and the “ordering principle” of international anarchy. They also propose numerous factors that can intensify or ameliorate the basic security problem, such as polarity, shifts in the overall balance of power, the “offense–defense balance,” and domestic politics. Several alternative approaches to international relations have challenged the basic realist account of the security problem, three of which are democratic peace theory, economic liberalism, and social constructivism. Furthermore, realism outlines various strategies that states can pursue in order to make themselves more secure, such as maximizing power, international alliances, arms racing, socialization and innovation, and institutions and diplomacy. Scholars continue to debate the historical roots, conceptual foundations, and predictive accuracy of realism. New avenues of research cover issues such as civil war, ethnic conflict, mass violence, September 11, and the Iraq War.