International Security & Defense

Calder Walton says both seek to topple the United States from atop world stage, with China's blend of money, influence, all-hands-on-deck approach posing the greater threat.

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.

According to the "Madman Theory" outlined by Daniel Ellsberg and Thomas C. Schelling, and embraced by Presidents Richard Nixon and Donald Trump, being perceived as mad can help make seemingly incredible threats—such as starting a nuclear war—more credible. However, recent research has largely concluded that the Madman Theory does not work. 

Scott Sagan asked Joseph S. Nye to revisit Nuclear Ethics, a book he published in 1986, in light of current developments in world affairs. In doing so, he found that much had changed but the basic usability paradox of nuclear deterrence remains the same. 

Joseph Nye considers U.S. options for risk reductions as nuclear threats escalate and China-Taiwan tensions rise.

Stephen Walt explains why Putin understood that Ukraine's fate was more important to Russia than it was to the West.

For months, evidence has accumulated that North Korea may be preparing its seventh nuclear explosive test. Continuous warnings by analysts and the media about this possibility are a sobering reminder that Pyongyang's continued pursuit of a larger nuclear arsenal remains a challenge for the Non-Proliferation Treaty and the nonproliferation regime. This continues to be the case even as the public and leaders around the world have largely shifted their attention to the nuclear dimensions of the war in Ukraine.

An analysis of Taiwan’s military value concludes that its reunification with China would improve Chinese submarine warfare and ocean surveillance capabilities, tipping the military balance in China’s favor. These findings have important implications for U.S. operational planning, policy, and grand strategy.

Stephen Walt writes that Western leaders should take the possibility of nuclear use more seriously, end their loose talk about war aims, and focus more attention on ending the war than on achieving an ill-defined but supposedly decisive victory.

Russia's war in Ukraine has brought questions of nuclear deterrence back to the fore, reminding world leaders that risk reduction must remain a top item on the global agenda. Because political and technological change will always introduce new issues, the work of maintaining a "just deterrence" is never done.