☢ MOD 15: Nuclear Weapons and U.S. Foreign Policy II

What is the problem of credibility in nuclear deterrence? Why does deterrence depend on credibility?

Credibility means an adversary believes a nuclear threat will actually be carried out. Deterrence fails if an opponent doubts that promise. Once a nuclear exchange begins, incentives change—leaders may hesitate to retaliate because of catastrophic costs. Therefore, effective deterrence requires believable threats that the state will respond, even at great risk.

What is extended deterrence and how does it affect credibility?

Extended deterrence uses the threat of nuclear retaliation to protect an ally or strategic partner. Example: the U.S. pledge to defend Western Europe during the Cold War. The credibility problem: would the U.S. risk Washington or New York to save Paris or London? Doubts over this led France and the UK to build their own nuclear forces.

How is credibility based on capabilities and resolve?

Capabilities: actual ability to execute a nuclear strike (weapons, delivery systems). Example: North Korea demonstrates capability through nuclear and missile tests. Resolve: the political will to follow through on a threat. Shown through crisis behavior, brinkmanship, and public commitments. Deterrence is credible only when a state has both strong capabilities + visible resolve.

How does a state demonstrate credibility in nuclear deterrence?

States signal credibility through: Brinkmanship – pushing crises to the edge to prove resolve. Tripwire forces – stationing small units in allied territories so any attack automatically triggers escalation. “Threat that leaves something to chance” – creating risk of accidental or uncontrollable escalation to pressure the adversary. Public pronouncements by democracies – since elected leaders face reputational costs if they back down.

How might national missile defense (NMD) influence the stability of nuclear deterrence?

Mutually Assured Destruction (MAD) depends on each side keeping a secure second-strike capability. Effective NMD could destroy incoming missiles and undermine MAD. This changes incentives: The protected state might be more willing to strike first or act recklessly. The vulnerable state might expand its arsenal or strike pre-emptively before defenses mature. Past example: Reagan’s Strategic Defense Initiative; today the U.S. maintains only limited NMD for small arsenals (e.g., North Korea).

What is nuclear proliferation? Why do states seek nuclear weapons, and why do others seek to prevent their spread?

Nuclear proliferation: the spread of nuclear weapons technology to new states. States pursue nukes because of: Security fears and mistrust of extended deterrence. Domestic politics – leaders gain prestige or political leverage. International status – desire for recognition and influence. The U.S. and international community oppose proliferation because: New nuclear states often lack secure second-strike systems. Domestic instability raises risks of accidents or theft. Could spark regional arms races and terrorist access to nuclear material.

Nuclear Deterrence Paradox

Nuclear weapons prevent war through fear of destruction but create instability if deterrence credibility or stability erodes.

Problem of Credibility

Difficulty convincing adversaries a nuclear threat will be executed; deterrence collapses if threats aren’t believed.

Extended Deterrence

Protecting allies by threatening nuclear retaliation; raises credibility doubts since leaders hesitate to risk homeland cities.

Capabilities

The physical means to deliver and survive a nuclear exchange – missile systems, warheads, command & control networks.

Resolve

The willingness of a state to carry out its nuclear threats even at great cost; demonstrated through crisis behavior and signals.

Brinkmanship

Strategy of escalating risk during crises to compel the adversary to back down, proving resolve in deterrence.

Tripwire Forces

Small forward-deployed military units whose attack would automatically draw their larger ally into conflict.

Threat That Leaves Something to Chance

Deliberately creating uncertainty or risk of accidental escalation to strengthen deterrent pressure.

Public Pronouncements by Democracies

Open commitments by democratic leaders that raise domestic and reputational costs of retreat, enhancing credibility.

National Missile Defense (NMD)**

Systems designed to intercept incoming nuclear missiles; may undermine MAD by weakening adversary second-strike ability.

Strategic Defense Initiative (SDI)**

Reagan-era plan for large-scale missile defense against Soviet attacks; never implemented due to cost and feasibility issues.

Limited NMD**

Post-Cold War U.S. policy focusing on protection against small arsenals or accidental launches from new nuclear states.

Secure Second-Strike Capability

Ability to absorb a nuclear attack and retaliate effectively; foundation of mutual deterrence stability.

Effects of NMD on Stability

Could encourage first strikes by protected states and arms buildups by vulnerable ones, destabilizing deterrence.

Nuclear Proliferation

Spread of nuclear weapons technology to additional states; increases global instability and credibility problems.

Causes of Nuclear Proliferation

Security fears, domestic politics, and quest for prestige or equality with established nuclear powers.

Risks of Nuclear Proliferation

Weak command and control in new nuclear states Accidental or unauthorized use Transfer of materials to terrorists Regional nuclear arms races

Credibility and Proliferation Link

States without faith in extended deterrence pursue their own nuclear weapons, increasing global instability.