When Does Competition Become Conflict? Technology, Geography, and the Offense–Defense Balance

Is there a meaningful offense–defense balance of technological, geographical, and human factors that substantially affects war likelihood and severity? Key contemporary policy debates are certainly infused with the notion, from the dangers of crisis instability in East Asia to the possible first-move advantages of cyber weaponry. Defensive realist theory, meanwhile, raises the possibility of inferring intent from external posture choices. Yet for offensive realists, such signaling is a doomed hope, because of aggressors’ incentives to conceal their hostile intentions before turning extant military technology to offensive ends. This article suggests that both perspectives misstate the causal role of the offense–defense balance. Competition may be a general condition of international politics—but it only manifests itself as a military conflict, defined as “cold” or ultimately “hot” war, under certain conditions. Specifically, the feasibility of advancing political goals via aggression rests on prevailing military technology, taken in its geographical context—that is, offense–defense calculations. Via three sub-theoretical cases—the “stopping power of water,” conventional blitzkrieg, and nuclear counterforce innovation—the article shows that the offense–defense balance affects conflict likelihood and severity even within offensive realism, specifically by affecting deterrence prospects. But this does not mean, as defensive realism posits, that the distinguishability of defense dominance promises a route out of the security dilemma.