Dramatic political, economic, and social changes across both the Greater Middle East and Latin America over the last several years—in some instances revolutionary, in others evolutionary—have had profound implications for global security generally and U.S. security specifically. Policymakers in Washington are hence confronted with the issue of how to respond to the various changes in these disparate regions in order to safeguard U.S. interests, promote Western values, and shape the security environment into the future. Whether and to what degree U.S. policymakers can influence the unfolding changes and shape outcomes remains to be seen. But if Washington is to achieve success in this regard though, it will likely only be possible through the skillful employment of a variety of policymaking tools, including development, diplomacy, and defense. The authors assess the changes across these two important regions, outline the implications for U.S. security and specifically for the U.S. military, and offer policy recommendations for the way forward.