International relations experts are pretty much down on everything nowadays. America, we are told, is incapable of global leadership: too discredited overseas, too few resources back home, too little will -- period. For a brief moment there, while China held up the global economy during the recent financial crisis, much credence was given to the notion that we were on the verge of a Chinese century. But that popular vision has also waned surprisingly quickly, and now the conventional wisdom centers on China’s great weaknesses, challenges and overall brittleness. Amazingly, where we spoke of a U.S.-China “G-2” arrangement just a few short years ago, now there is a sense that no one is in charge.