NEW YORK — In 2009, Forbes magazine named U.S. President Barack Obama and Chinese President Hu Jintao the "world's most powerful people." In 2010, we will discover that neither has the power to keep U.S.-Chinese relations on track. That is bad news for those who believe that U.S.-China cooperation is essential for reviving the global economy, meeting the challenge of climate change, containing threats of nuclear proliferation, and managing a host of other problems without borders. It is also bad news for America and China.

Ten is the number to watch: America's 10 percent unemployment and China's potential 10 percent GDP growth are set to collide like weather fronts generating a storm. American populism will meet Chinese pride. And the fevered political climate created by U.S. midterm elections means that the world's most important bilateral relationship is headed for real turbulence this year.

America and China now live with a kind of mutually assured economic destruction, and both presidents know it. The U.S. needs China to finance its mounting debt, and China needs Americans to buy its products.