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.

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.

After World War II, "trading states" seemed to be charting a new path forward. But small was not beautiful. Even great powers found themselves negotiating larger markets through economic associations with others. It's time the United States became such a power.

"All of these pathologies were evident in the failure to prevent or appropriately respond to the Mumbai attacks. There was in fact significant intelligence suggesting a seaborne terrorist attack was likely, and even that prominent sites such as the Taj Hotel would be targeted. This information, however, was ignored by several key bureaucratic actors—including the Coast Guard and the Maharashtra state director-general of police—because it was deemed unactionable. Others, such as the Maharashtra Anti-Terrorism Squad, at least attempted some kind of preparation. The differences in readiness highlight the extent of fragmentation among the security apparatus. Even when Mumbai police tried to take preventive action, they lacked the manpower to sustain increased security at the hotels. Once the attack occurred, the security forces did not have sufficient night-vision equipment, heavy weaponry, or information about the attack sites, leading to a long response time and the emergence of a disastrous siege...."

The Anglo-Japanese alliance of 1902–23 illustrates the importance of economic side payments as a method for forming and maintaining alliances. It also shows, however, the influence of domestic factors on constraining these types of payments. Security concerns often lead a nation to offer side payments to a potential ally, but domestic political constraints, partisanship, and changing strategic needs account for the variation in the economic-security linkage.

"As the American political system hurtles toward its quadrennial encounter with the oracle of democracy, it is worth our while to take stock of the country's place in a world beset by bewilderingly rapid change. (Heaven knows none of the candidates will bother to do this.) I want to suggest that an old yet generally neglected subject remains particularly relevant: the relationship between the size of political units and the effective scale of systems of economic production and exchange. Another way to describe this relationship is by recourse to the hoary scholarly phrase "political economy", a term of art that has unfortunately gone out of style...."