Summary

The U.S. Congress has broad constitutional powers to shape foreign policy. However, Congress rarely shapes foreign policy as an equal partner with the president. Politics has the potential to enhance or lessen Congress’s role. What explains changes over time in congressional power in foreign policy? Why does Congress assert itself on some issues but less so on others in U.S. foreign policy? What strategies or tools does Congress employ to shape the nation’s foreign policy? The lens of New Institutionalism, two presidencies, and presidential unilateralism connect in useful ways to help explain these kinds of key questions in foreign policy. They offer scholars a future framework to continue to enhance theories explaining variation in congressional assertiveness in foreign policy.