The separation of powers has spawned a great deal of debate over the roles of the president and Congress in foreign affairs, as well as over the limits on their respective authorities, explains this …

U.S. missile defense in the twenty-first century is focused on emerging threats from North Korea and Iran, but critics say these systems are too costly and largely unproven.

For many policymakers, economic sanctions have become the tool of choice to respond to major geopolitical challenges such as terrorism and conflict.