What role does identity and technology play in the conceptualisation of Defensive realism ?

Defensive realism holds that the international system rewards moderation: states seek an appropriate amount of power, not the maximum, because excessive expansion provokes balancing and is self-defeating. Waltz supplies the structural premise; Jervis, Van Evera, Snyder and Glaser develop it.

Technology enters through the offence-defence balance. Whether the prevailing military technology favours attack or defence determines how severe the security dilemma is. Where defence has the advantage and defensive weapons can be distinguished from offensive ones, states can secure themselves without threatening others, and cooperation is possible. Where offence dominates, even security-seeking states appear threatening — Jervis's argument in Cooperation Under the Security Dilemma (1978), and Van Evera's account of the cult of the offensive before 1914. Nuclear weapons, on this reading, strongly favour the defence, which is why defensive realists expect deterrence to be stable. Cyber and emerging technologies unsettle this, because attribution is hard and offence and defence are not distinguishable.

Identity enters through perceived intent. Defensive realism must explain why states sometimes misjudge each other, and the answer is perception. Jervis's spiral model shows how a state's defensive measures are read as aggressive because of prior beliefs about the other's character. Glaser separates security-seekers from greedy states, and since a state's type is not observable, judgements about identity and intent become unavoidable.

Assessment. These two moves distinguish defensive from offensive realism, but they also make the theory less purely structural, since it now depends on unit-level perception — which is what neoclassical realism later formalised.