American Enterprise Institute for Public Policy Research: a private, nonpartisan, not-for-profit institution dedicated to research and education on issues of government, politics, economics, and social welfare.

Carnegie Endowment for International Peace: a private, nonprofit organization dedicated to advancing cooperation between nations and promoting active international engagement by the United States.

Cato Institute - Individual Liberty, Free Markets, and Peace: the mission of the Cato Institute is to increase the understanding of public policies based on the principles of limited government, free markets, individual liberty, and peace.

Center for Defense Information: provides expert analysis on various components of US national security, international security, and defense policy. CDI promotes wide-ranging discussion and debate on security issues such as nuclear weapons, space security, missile defense, small arms, and military transformation.

Council on Foreign Relations: an independent, nonpartisan think tank and publisher dedicated to being a resource for 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. Also publishes Foreign Affairs.

International Crisis Group: the world’s leading independent, non-partisan, source of analysis and advice to governments, and intergovernmental bodies on the prevention and resolution of deadly conflict.