My theory since before 9/11 has been that China has been building up our enemies in the Middle East (as well as Southeast Asia, Africa, and Central America) to dilute our forces in Asia so they can make a full-court press there. As I'm reading things the speed and strength of our success in Afghanistan and Iraq threw a wrench into that game plan, and now they're clinging to Iran desperately to try to salvage their war plan. If we manage to defuse the time bombs in the Middle East it adds obstacles to their plans in Asia.
Make that "Latin America", to include Chinese activity in South America. Not to mention the Triad infiltration of Canada over the past couple decades.