Nuclear Issues

This year's G7 summit in Hiroshima sees nuclear disarmament and non-proliferation sitting high on the agenda, amid rising tensions between the nuclear states and an increasingly divided international order.  Six contributors offer their analyses, including the Belfer Center's Mayumi Fukushima.

Mariana Budjeryn's Inheriting the Bomb tells the story of how Ukraine came into possession of the world's third-largest nuclear arsenal—larger than the combined stockpiles of China, France, and the United Kingdom at the time—and decided to disarm peacefully a few years later. Ukraine's denuclearization was far from a straightforward process. After initially renouncing nuclear weapons, Ukrainian officials sought recognition that their newly independent country was a rightful heir to part of the Soviet cache, deserving of equal treatment, financial compensation, and pledges that disarmament would not endanger Ukraine's security. 

Earlier this month, South Korean President Yoon Suk-yeol set off alarms. In an off-the-cuff remark, he warned that Seoul might need to develop nuclear weapons—or demand redeployment of U.S. nuclear arms to the Korean Peninsula—to counter North Korean nuclear threats. In doing so, Yoon spotlighted a popular view once reserved for hawkish commentators, defense intellectuals, and former military officials. Keeping nuclear weapons out of South Korea will ultimately be a U.S. responsibility that requires addressing both the deteriorating security environment and the domestic drivers underlying Yoon’s statement.

Although Russia has relied exclusively on conventional weapons for its invasion of Ukraine, behind the scenes lurks Moscow’s massive nuclear arsenal. Hours before Russian forces crossed into Ukraine, Russian President Vladimir Putin reminded the world that his country was “one of the most powerful nuclear states” and that anyone who interfered with his war in Ukraine or threatened Russia directly would face “consequences that you have never faced in your history.” Three days later, as global outrage grew, Putin ordered Russia’s nuclear forces to a higher level of readiness. Even without these explicit threats, Russia’s nuclear deterrent would have prevented Western countries from intervening in Ukraine. Beyond supplying Kyiv with anti-armor and light air defense weapons, they will not come to Ukraine’s defense for fear of nuclear escalation, as U.S. President Joe Biden and other NATO leaders have made abundantly clear. Now that Putin’s attempts to seize Kyiv have been thwarted, there is a risk he will use tactical nuclear weapons to bring Ukraine to its knees. And while this scenario remains unlikely, neither Ukraine nor NATO can do anything to prevent it from happening.

This is a particularly bitter pill to swallow for Ukraine, since it was once home to the world’s third-largest cache of nuclear weapons. After the collapse of the Soviet Union, Ukraine inherited a significant slice of the Kremlin’s nuclear arsenal. But in 1994, the newly independent country decided to surrender that arsenal in exchange for assurances from Russia, the United Kingdom, and the United States that its sovereignty and territorial integrity would be respected. The agreement, known as the Budapest Memorandum, is one that many Ukrainians have come to regret—first in the wake of Russia’s 2014 annexation of Crimea and invasion of eastern Ukraine, and now even more so after its all-out assault on the country. If Ukraine had held on to its arsenal, many have argued, Putin would never have dared to invade the country.

The Biden-Putin summit in Geneva did not disappoint the very low expectations set out for it. To move beyond symbolism and signaling, however, the Biden-Putin proclamation has to be translated into practical progress.

William d'Ambruoso explains why high-level engagement, built on a baseline of deterrence, lessens the chances of war and opens the way for future cooperation in North Korean–U.S. relations.

The Bulletin of Atomic Scientists has published a document from the Pugwash Conference on Science and World Affairs concerning nuclear problems and tensions in the time of COVID-19. The document has been co-signed by a large number of Pugwash colleagues and personalities.

Mariana Budjeryn recounts Ukraine's surrender of its inherited nuclear arsenal and the signing of the Budapest Memorandum by the United States, United Kingdom, and Russia. While the memorandum did not specify the assistance Ukraine was to receive if it became a victim of aggression, Ukrainians were led to believe that the United States would uphold its commitments to their security in the time of need, as Ukraine upheld its commitment to nuclear nonproliferation norms.