Brookings Institution: a nonprofit public policy organization based in Washington, DC. http://www.brookings.edu/
RAND: The RAND Corporation is a nonprofit institution that helps improve policy and decision making through research and analysis. http://www.rand.org
Strategic Studies Institute: U.S. Army War College's institute for geostrategic and national security research and analysis. https://ssi.armywarcollege.edu
Center for Strategic and International Studies (CSIS): A bipartisan, nonprofit organization headquartered in Washington, DC, CSIS provides strategic insights and policy solutions to decision makers in government, international institutions, the private sector, and civil society. http://csis.org/
Council on Foreign Relations (CFR): is a nonprofit and nonpartisan membership organization dedicated to improving the understanding of U.S. foreign policy and international affairs, based in NYC. http://www.cfr.org/
Center for Naval Analyses (CNA): CNA is a non-profit research organization that operates the Center for Naval Analyses and the Institute for Public Research. It is based in VA. http://www.cna.org/
Center for a New American Security (CNAS): As an independent and nonpartisan research institution, informs the national security leaders of today and tomorrow. Established in 2007, it is located in Washington, DC. http://www.cnas.org/
World Resources Institute (WRI) : Created AQUEDUCT measuring and mapping water risk tool to track water risks at a scale appropriate for developing sound business and investment strategies. https://www.wri.org
The Climate Institute The Climate Institute has been in a unique position to inform key decision-makers, heighten international awareness of climate change, and identify practical ways of achieving significant emissions reductions. Located in Washington, DC.
Carnegie Council for Ethics in International Affairs. Founded by Andrew Carnegie in 1914, CCEIA is an independent, nonprofit, educational 501(c)3 institution serving international affairs professionals, teachers and students, and the attentive public. See "climate change" under resources.