President Obama’s inauguration in 2009 seemed to herald a new era in US foreign policy and international relations. But the Bush years had left a formidable set of problems - war in Iraq and Afghanistan, terrorism, nuclear proliferation in Iran and the rise of China. In this unit you will explore these challenges facing the USA. You will learn about the position of the USA in the international system, how to analyse US economic and political power in international politics, and be able to make sense of constrains on, and choices open to, US policy in the 21st Century. This study unit is just one of many that can be found on LearningSpace, part of OpenLearn, a collection of open educational resources from The Open University. Published in ePub 2.0.1 format, some feature such as audio, video and linked PDF are not supported by all ePub readers.