Is Nuclear Proliferation the Logical Outcome of Unconstrained Power?

The global nuclear nonproliferation regime rests on a central assumption. States refrain from acquiring nuclear weapons because international law, security guarantees, and collective norms make such weapons unnecessary for survival. 

The Nuclear Non-Proliferation Treaty (NPT), which entered into force in 1970, now includes 191 states. It embodies this expectation: non-nuclear states agree to forgo nuclear arms in exchange for security assurances, access to peaceful nuclear technology, and progress toward disarmament.

But the durability of this bargain depends on credibility. When international rules yield to power, the incentive to remain non-nuclear declines. In a system where stronger states repeatedly use military force against weaker ones, nuclear weapons appear not as reckless instruments but as the ultimate guarantee of sovereignty. 

States without nuclear weapons face coercion, military pressure, and invasion. Under these conditions, nuclear proliferation emerges not as irrational behavior but as a logical response to power politics unconstrained by legal treaties and collective norms. 

Ukraine and the Collapse of Security Assurances

After the collapse of the Soviet Union, Ukraine inherited the world's third-largest nuclear arsenal. In 1994, Kyiv agreed to relinquish these weapons and join the NPT as a non-nuclear state. The United States, the United Kingdom, and Russia, in return, signed the Budapest Memorandum, affirming commitments to respect Ukraine's independence, sovereignty, and territorial integrity.

Yet Russia annexed Crimea in 2014 and launched a full-scale invasion of Ukraine in 2022. A nuclear-armed state violated assurances that accompanied Ukraine's nuclear disarmament and attacked a state that had relinquished the ultimate means of deterrence.

For policymakers worldwide, the sequence produces a powerful lesson. A state surrendered nuclear weapons and later faced invasion by a nuclear-armed neighbor. While the Budapest Memorandum did not constitute a formal defense treaty, it symbolized a central promise of the post–Cold War nonproliferation order that states that renounced nuclear weapons would not suffer strategic vulnerability as a result.

The breakdown of that expectation reshaped the strategic conversation. Nuclear weapons deter aggression by raising the risks of escalation to catastrophic levels. Conventional military superiority loses much of its value when nuclear retaliation enters the equation.

North Korea's Strategic Calculation

For decades, Pyongyang has framed its nuclear program as essential for national survival. Kim Jong Un emphasizes that nuclear weapons protect the country from external aggression and guarantee the continuation of the regime.

For North Korean leaders, recent events validate this strategy. States that lacked nuclear deterrents experienced regime collapse or foreign intervention. Iraq was invaded in 2003. Libya dismantled its nuclear program in 2003 and later faced Western military intervention during the 2011 uprising.

North Korea followed the opposite path. It pursued nuclear weapons relentlessly despite sanctions and diplomatic isolation. The result is a regime that faces pressure yet remains free from direct military attack aimed at regime change.

This contrast reinforces Pyongyang's central narrative: nuclear weapons transform a vulnerable state into a strategically untouchable one. A credible nuclear arsenal raises the costs of military confrontation to unacceptable levels for potential adversaries.

Iran and the Nuclear Threshold

Tehran has maintained that its nuclear program serves peaceful purposes while simultaneously advancing uranium enrichment capabilities that shorten the technical distance to nuclear weapons.

Regional conflicts — including recent US and Israeli attacks — intensify debate within Iran about long-term security. Leaders evaluating national defense confront a stark comparison between states that possess nuclear deterrents (North Korea) and those that do not (Iraq, Libya).

For Iranian decision-makers, nuclear weapons represent the most reliable protection against coercion by stronger states.

Next Tier of Proliferation Pressures

Proliferation pressures extend beyond authoritarian regimes. Democratic governments facing severe security threats confront similar strategic calculations.

In East Asia, Japan and South Korea confront both North Korea's expanding nuclear arsenal and China's rising military power. Although both democracies maintain non-nuclear principles, growing debates in both countries about nuclear deterrence reveal anxiety about regional security and the reliability of US security guarantees. 

The most vulnerable democracy remains Taiwan, facing constant military pressure from China. 

Extended deterrence, or the promise that the United States will defend allied states — formally with respect to South Korea and Japan, informally with Taiwan — historically discouraged nuclear proliferation among American allies. Any weakening of that commitment strengthens arguments for independent nuclear deterrents.

When Guarantees Fail, Nukes Follow

Global nuclear proliferation is often framed as a dangerous anomaly that diplomacy and sanctions must prevent. Yet from the perspective of vulnerable states, the pursuit of nuclear weapons reflects a rational strategic choice.

North Korea believes its nuclear arsenal guarantees regime survival. Iranian leaders observe the same pattern and draw similar conclusions about sovereignty and deterrence. Ukrainian strategists confront the consequences of disarmament under failed assurances. South Korea, Japan, and especially Taiwan face growing uncertainty in East Asia.

Each case reinforces the same lesson: nuclear weapons deter aggression more effectively than international or bilateral treaties.

The spread of nuclear weapons, therefore, reflects a deeper problem within the international system. When unconstrained state power overrides legal commitments and security guarantees, the incentives that sustain nonproliferation erode. States respond by seeking the most powerful deterrent available.

Nuclear proliferation emerges as the logical outcome of a global environment of legally unconstrained, "might determines right" power politics. 

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Author: Joseph Yi, associate professor of political science at Hanyang University