The leaders of 20 of the world’s important economies are coming to town, and the residents of this good city are not in a welcoming mood. How could they be? A sign of the hassles ahead is the security fence that snakes for more than two miles around several downtown city blocks, where the G20 leaders will meet June 26-27.

The idea of a "G-2" was first introduced by C. Fred Bergsten, director of Peterson Institute for International Economic, as a mechanism for promoting agreement between the two sides primarily to address international economic issues. However, it migrated to strategic issues...

The summit is just the latest example of the growing tendency of the United States to take important issues – such as financial stability, climate change, and nonproliferation – outside the UN system. The Group of 20 has become the prevailing symbol of this trend of addressing complex international issues in informal settings...