Articles

The defining question about global order for this generation is whether China and the United States can escape Thucydides’s Trap. The Greek historian’s metaphor reminds us of the attendant dangers when a rising power rivals a ruling power—as Athens challenged Sparta in ancient Greece, or as Germany did Britain a century ago. Most such contests have ended badly, often for both nations, a team of mine at the Harvard Belfer Center for Science and International Affairs has concluded after analyzing the historical record. In 12 of 16 cases over the past 500 years, the result was war. When the parties avoided war, it required huge, painful adjustments in attitudes and actions on the part not just of the challenger but also the challenged.

In the United States and Europe, many believe that the best way to prevent Russia’s resumption of its historic imperial mission is to assure the independence of Ukraine. They insist that the West must do whatever is required to stop the Kremlin from establishing direct or indirect control over that country. Otherwise, they foresee Russia reassembling the former Soviet empire and threatening all of Europe. Conversely, in Russia, many claim that while Russia is willing to recognize Ukraine’s sovereignty and territorial integrity (with the exception of Crimea), Moscow will demand no less than any other great power would on its border. Security on its western frontier requires a special relationship with Ukraine and a degree of deference expected in major powers’ spheres of influence. More specifically, Russia’s establishment sentiment holds that the country can never be secure if Ukraine joins NATO or becomes a part of a hostile Euro-Atlantic community. From their perspective, this makes Ukraine’s nonadversarial status a nonnegotiable demand for any Russia powerful enough to defend its national-security interests.

States have long worried that their dependence on oil gives producers a means of coercion. The oil market, however, is far larger and more integrated than it used to be. The potential for coercion differs across a series of distinct market segments. In this varied market, the United States remains the dominant force.

This article describes the status of China’s military and civilian nuclear programs, fissile material production and associated nuclear facilities, and the Chinese nuclear experts and officials’ perspectives on the nuclear terrorism threat. It gives details of China’s nuclear security practices, attitudes, and regulations, as well as identifying areas of concern. The article recommends ways to strengthen China’s nuclear material protection, control, and accounting systems and suggests opportunities for increased international cooperation.

U.S. scholars and policymakers commonly worry that a lack of "energy security" hurts U.S. national security, yet few have analyzed the links between states' energy requirements and the probability of military conflict. An investigation of these links identifies threats to U.S. national security flowing from other countries' consumption of oil, rather than just U.S. consumption. Furthermore, while many of the security threats associated with Persian Gulf oil have decreased, new oil-driven dangers are emerging in Northeast Asia.

The upcoming transition in North Korea’s leadership will not inevitably bring about a collapse of government, but the potential consequences of such an event necessitate advance and combined planning. It is imperative that China, South Korea, and the United States develop a coordinated response, as each of these countries could take destabilizing action to protect their individual interests. A relatively benign collapse could require 260,000 to 400,000 troops to gain control of North Korea’s nuclear weapons, prevent humanitarian disaster, manage regional refugees, and ensure stable U.S.-Chinese relations. Civil war or war on the peninsula would only increase these requirements.

States use wedge strategies to prevent hostile alliances from forming or to dis­perse those that have formed. These strategies can cause power alignments that are otherwise unlikely to occur, and thus have significant consequences for international politics. How do such strategies work and what conditions promote their success? The wedge strategies that are likely to have significant effects use selective accommodation—concessions, compensations, and other inducements—to detach and neutralize potential adversaries. These kinds of strategies play important roles in the statecraft of both defensive and offensive powers. Defenders use selective accommodation to balance against a primary threat by neutralizing lesser ones that might ally with it. Expansionists use se­lective accommodation to prevent or break up blocking coalitions, isolating opposing states by inducing potential balancers to buck-pass, bandwagon, or hide. Two cases—Great Britain’s defensive attempts to accommodate Italy in the late 1930s and Germany’s offensive efforts to accommodate the Soviet Union in 1939—help to demonstrate these arguments. By paying attention to these dynamics, international relations scholars can better understand how balancing works in specific cases, how it manifests more broadly in interna­tional politics, and why it sometimes fails in situations where it ought to work well.