The Brookings Institution is a nonprofit public policy organization based in Washington, D.C. One of oldest and most influential U.S. public policy think tanks, Brookings conducts research and education in the social sciences, primarily in economics, metropolitan policy, governance, foreign policy, and global economy and development.

The Center for Strategic and International Studies is a bipartisan Washington, D.C., foreign policy think tank. The center conducts policy studies and strategic analyses on political, economic and security issues, focusing on technology, public policy, international trade and finance, and energy.

The Council on Foreign Relations (CFR) is an independent, nonpartisan membership organization, think tank, and publisher dedicated to being a resource for its members, government officials, business executives, journalists, educators and students, civic and religious leaders, and other interested citizens in order to help them better understand the world and the foreign policy choices facing the United States and other countries.

The Federation of American Scientists (FAS) is a nonpartisan, nonprofit organization intent on using science and scientific analysis to attempt make the world more secure. FAS was founded in 1945 by scientists who worked on the Manhattan Project to develop the first atomic bombs. These scientists felt that science had become central to many key public policy questions, and that they had a unique responsibility to inform public policy makers of potential dangers from scientific and technological advances, and to show how good policy could increase the benefits of new scientific knowledge. Known for priding itself on an ability to bring together people from many disciplines and organizations, FAS attempts to address critical policy topics that are not well covered by other organizations.

The International Crisis Group is generally recognised as the world’s leading independent, non-partisan, source of analysis and advice to governments, and intergovernmental bodies like the United Nations, European Union and World Bank, on the prevention and resolution of deadly conflict.

RAND Corporation is a nonprofit global policy think tank first formed to offer research and analysis to the United States armed forces by Douglas Aircraft Company. It is currently financed by the U.S. government and private endowment, corporations including the healthcare industry, universities and private individuals. The organization has long since expanded to working with other governments, private foundations, international organizations, and commercial organizations on a host of non-defence issues. RAND aims for interdisciplinary and quantitative problem solving via translating theoretical concepts from formal economics and the hard sciences into novel applications in other areas; that is, via applied science and operations research.

The Strategic Studies Institute (SSI) is the U.S. Army's institute for strategic and national security research and analysis. It is part of the U.S. Army War College. SSI conducts strategic research and analysis to support the U.S. Army War College curricula, provides direct analysis for Army and Department of Defense leadership, and serves as a bridge to the wider strategic community. It is located at Carlisle Barracks, Pennsylvania.