Toward a G-2
I have proposed since 2004 that the United States and China create an informal G-2 to help steer the world economy. The reason is simple: Progress is impossible on most important global economic issues without agreement by these two global economic superpowers. Examples including exchange rates and the international monetary system, the world trade regime and climate change. (The one notable exception is financial regulatory reform, where China is not yet an important player so most decisions remain with a subset of the membership of the Financial Stability Board.)
There are now three global economic superpowers, the European Union along with China and the United States. But Europe, or even the more integrated euro area, speaks with a single voice on very few issues. Moreover, its current economic weakness limits its influence on most topics. So a G-2 is the only practical possibility for achieving effective global economic leadership.