State A builds a missile defense system explicitly to neutralize missile threats from State C, a regional rival. State B, which has no conflict with State A, begins increasing its offensive missile arsenal in response. Which concept best explains State B's behavior?
APower maximization — State B is exploiting the situation to extend its regional dominance
BThe security dilemma — State A's defensive action appears threatening to State B due to the dual-use nature of capabilities
CPreventive war logic — State B anticipates State A will attack once the defense system is complete
DOffensive realism — rational states always respond to capability increases with capability increases
This is a textbook security dilemma scenario: State A takes a genuinely defensive action (missile defense), but State B cannot verify State A's intentions from capabilities alone. A missile defense system that neutralizes State C's deterrent also neutralizes State B's deterrent — the same capability serves both defensive and offensive strategies. State B's rational response is to rebuild deterrence by increasing its offensive capabilities, even though neither state sought confrontation. Defensive realism identifies this as structural: the problem is not bad intentions but unverifiable intentions combined with inherently dual-use military technology.
Question 2 Multiple Choice
What is the fundamental disagreement between defensive and offensive realism about state behavior?
AWhether anarchy creates self-help imperatives — defensive realists deny anarchy while offensive realists accept it
BWhether states seek to maximize power or merely acquire enough power to ensure security
CWhether nuclear weapons stabilize or destabilize international relations
DWhether institutions can effectively constrain state behavior in the long run
Both defensive and offensive realism accept anarchy as the fundamental condition of international politics, and both accept self-help as its implication. The core disagreement is about what rational states optimize for. Offensive realism (Mearsheimer) argues that more power always means more security, so rational states relentlessly seek to maximize their power share, ultimately pursuing hegemony. Defensive realism (Waltz, Jervis) argues that hegemony-seeking is counterproductive because it triggers balancing coalitions, so rational states seek enough power to defend themselves and no more. This produces very different predictions about state behavior.
Question 3 True / False
According to defensive realism, a state that acquires significantly more military power than needed for defense may actually become less secure as a result.
TTrue
FFalse
Answer: True
This is a core claim of defensive realism and one of its sharpest departures from offensive realism. When a state's power visibly exceeds what is needed for defense, other states interpret this as revisionist ambition — a signal that it seeks dominance. This triggers balancing behavior: potential rivals form coalitions, increase their own military spending, and align against the expanding state. The net result is that the power-accumulating state faces a more threatening environment than it did before the buildup. The implication is that optimal security comes from maintaining roughly proportional power and clearly signaling status-quo intentions, not from maximizing capabilities.
Question 4 True / False
The security dilemma could be fully resolved if states simply communicated their intentions clearly and transparently, because misperception is fundamentally a communication failure.
TTrue
FFalse
Answer: False
This misunderstands the structural nature of the security dilemma. Even with perfect transparency about intentions, the dilemma persists because military capabilities are inherently dual-use: the same army that defends also threatens, the same missiles that deter also strike. A state can honestly declare defensive intentions while simultaneously possessing offensive capabilities — and other states have no way to guarantee those intentions will hold forever or under future leadership. The residual ambiguity is irreducible. This is why Jervis called it a 'dilemma' rather than a 'misunderstanding': even with good communication, some degree of mutual vulnerability and uncertainty remains structurally unavoidable under anarchy.
Question 5 Short Answer
Why, according to defensive realism, do wars occur even between states that both genuinely prefer peace?
Think about your answer, then reveal below.
Model answer: Because intentions are unobservable while capabilities are not. Genuinely defensive military actions look identical to offensive preparations from the outside. When each state responds defensively to the other's apparent threat, the responses themselves look threatening, creating an escalatory spiral that neither side intended.
This is the 'tragic' insight at the heart of defensive realism: conflict can emerge from structure, not malice. Jervis's spiral model captures the mechanism — each round of defensive arming is read as aggression by the other side, triggering a further defensive response that again looks like aggression. The spiral does not require any party to have aggressive intentions; it only requires that capabilities signal something intentions cannot confirm. The policy implication is that reassurance and confidence-building measures can reduce spirals, but cannot eliminate them entirely, because the structural ambiguity of dual-use capabilities is never fully resolvable in an anarchic system.