Introduction
Bernard Brodie observed that the chief purpose of a military establishment was once to win wars, but with the advent of nuclear weapons, its paramount purpose became to avert them. In the contemporary geopolitical landscape, the ongoing conflict in Ukraine and heightened tensions on the Korean Peninsula show that nuclear deterrence remains potent, yet its operational logic has evolved from pure war prevention to facilitating conventional brinkmanship, illustrating Glenn Snyder's Stability-Instability Paradox.
The Stability-Instability Paradox in the Russia-Ukraine War
The Russia-Ukraine conflict demonstrates the dual dynamics of nuclear deterrence in great-power rivalry:
- Strategic Stability vs. Conventional Instability: Mutual Assured Destruction (MAD) has maintained strategic stability by averting a direct military clash between NATO and the Russian Federation. However, under this nuclear umbrella, Russia has waged high-intensity conventional war. Strategic signaling, including intermediate-range missile posturing such as the deployment of Oreshnik systems, serves to deter direct Western intervention, validating Glenn Snyder's thesis that strategic nuclear parity encourages sub-nuclear revisionism.
- The Proliferation Security Dilemma: Ukraine surrendered the world's third-largest nuclear arsenal under the 1994 Budapest Memorandum in exchange for security assurances. Russia's subsequent invasions have intensified the systemic security dilemma conceptualized by John Herz and Robert Jervis, demonstrating to non-nuclear states that diplomatic assurances from major powers are vulnerable to geopolitical calculations and undermining global non-proliferation regimes.
Asymmetric Deterrence and Nuclear Compellence in North Korea
The Korean Peninsula highlights the utility of atomic arsenals for weaker regimes facing superior adversaries:
- Rational Survival and Regime Security: For Pyongyang, nuclear weapons serve as an asymmetric equalizer against conventional and technological inferiority. North Korea's constitutional codification of an irreversible nuclear status aligns with Kenneth Waltz's structural realist argument that nuclear weapons provide absolute defensive deterrence against foreign-imposed regime change.
- Shift toward Coercive Compellence: Resonating with Scott Sagan's organizational critiques of nuclear proliferation, Pyongyang has transitioned from purely defensive deterrence toward tactical compellence. The development and mass production of tactical and battlefield nuclear systems enable North Korea to engage in coercive diplomacy against regional rivals under the threshold of full-scale retaliation.
Erosion of Extended Deterrence
The proliferation of intercontinental ballistic missile (ICBM) capabilities in adversary states poses structural challenges to traditional alliances:
- Credibility of the Nuclear Umbrella: As North Korea's delivery systems threaten the continental United States, questions emerge regarding Washington's willingness to trade an American city for Seoul or Tokyo. This credibility deficit in extended deterrence has intensified domestic debates within South Korea and Japan regarding independent nuclear deterrence capabilities.
Conclusion
While nuclear deterrence continues to avert direct major-power systemic wars, it has increasingly become an enabler of lower-tier conventional revisionism and coercive brinkmanship. Ensuring durable strategic stability requires moving beyond unconstrained deterrence toward revived multilateral arms control frameworks, strategic dialogue, and robust crisis-communication mechanisms.