The Middle East is unquestionably President Obama's toughest foreign policy challenge. The region is a complex clash of interests, histories, cultures and religions. It cannot be understood through stereotype or one-size-fits-all generalizations. Every country of the Middle East, and every conflict in the Middle East, has its own history and its own challenges. There's only so much an American president can do to influence events. That influence depends on a clear understanding of the players motivations and America's limitations. Here's a guide to Obama's Middle East policies.