On 5 January 2012, President Obama announced a new defence strategic guidance entitled "Sustaining U.S. Global Leadership: Priorities for 21st Century Defense". This new guidance is significant because it is explicitly intended to reshape future Department of Defense (DOD) priorities, activities, and budget requests for the next decade. While the guidance is intended to steer DOD decision-making as it reduces defence spending by about $487 billion over the next 10 years, to meet the initial budget caps set in the Budget Control Act (BCA) of 2011, it does not account for the possibility of sequestration, further significant, across-the-board cuts that could be required pursuant to implementation of the BCA. This book highlights and analyses key strategic-level issues raised by the new guidance.