" over the rest of this century—than any other grouping. The G2 comprises just two countries —the United States and China—which together represent about 40 percent of the world’s GDP and 50 percent of its military spending. The G2 is not an alliance or a forum for decision-making. Rather, it underlines the importance of the relationship between these two countries—and their new rivalry—and its impact on the entire world. "

― Daniel Yergin , The New Map: Energy, Climate, and the Clash of Nations