Abstract

This chapter examines realism as a dominant explanation of why and how states have sought security. It first considers the basic features of realist theory, including its emphasis on the implications of international anarchy and the importance of power, before discussing major divisions within the realist family, along with their implications for states’ security policies and war. The most fundamental division is between structural realism and motivational realism. The chapter proceeds by looking at the debate between Kenneth Waltz’s structural realism, offensive realism, and defensive realism. In contrast to Waltz and offensive realism, defensive realism argues that the risks of competition can make cooperation a state’s best strategy. The chapter illustrates how these different arguments result in divergent predictions for how China’s continuing economic growth is likely to influence international security. It suggests that war is more likely when the offence-defence balance favours offence.