Editors' foreword.

The emergence of China and India on the geopolitical landscape will define international affairs in the 21st century. Together, the two countries represent more than a third of the world's population, use over a quarter of the world's energy and constitute almost a fifth of the world economy. Indeed, much has been written about the shifting global balance of power and the impending decline of U.S. hegemony in the face of emergent and increasingly influential states like China and India. Less explored, however, are the relations between the two countries. Are China and India destined for confrontation, as is often assumed, or cooperation?

Given their acrimonious history, which came to a head in a bitter border war in 1962, it is reasonable to conclude that competition between China and India is inevitable. But while the border war looms large in the two countries' shared history, cooperation between them is not without precedent. India's first prime minister, Jawaharlal Nehru, envisioned a China and India unified by a common history of exploitation by the West--a vision that he called "Asianism." In 1954, the two countries established a set of norms aimed at preserving amicable relations between them known as the Five Principles of Peaceful Coexistence. More recently, China and India have sought to engage more strategically on a range of issues, including trade, climate change and poverty alleviation. For this issue of the Journal, we asked contributors to reflect on whether Sino-Indian relations are inherently cooperative or competitive, and to explore the broader implications of this relationship for the international community.

Francine R. Frankel begins by examining the geopolitical and security dynamics at play between China and India. Skeptical of official proclamations of friendship made by politicians in both countries, Frankel predicts a dangerous and growing rivalry between the two neighbors. Moving from the Indian Ocean to the Himalayan rivers, Jonathan Holslag investigates the possibility of water war between China and India, arguing that Indian fears about Chinese water diversion projects are premature. Cooperation on this important issue will be difficult, according to Holslag, given mutual distrust on both sides.

Our next two authors take a closer look at the complex interplay of geopolitics that affect--and to some extent define--Sino-Indian relations. Jingdong Yuan examines the "Pakistan factor" and discusses how China's...