I actually want to focus in on this think tank issue a little bit. Here's the mission statement for The Heritage Foundation:
Founded in 1973, The Heritage Foundation is a research and educational institute - a think tank - whose mission is to formulate and promote conservative public policies based on the principles of free enterprise, limited government, individual freedom, traditional American values, and a strong national defense.
So they're unabashedly conservative. And here's The American Enterprise Institute:
The American Enterprise Institute for Public Policy Research is a private, nonpartisan, not-for-profit institution dedicated to research and education on issues of government, politics, economics, and social welfare. Founded in 1943, AEI is home to some of America's most accomplished public policy experts...AEI's purposes are to defend the principles and improve the institutions of American freedom and democratic capitalism--limited government, private enterprise, individual liberty and responsibility, vigilant and effective defense and foreign policies, political accountability, and open debate.
AEI, for their part, makes a play for nonpartisanship, but nevertheless puts forward the conservative principles animating their work, "limited government, private enterprise, individual liberty and responsibility," and so on. Now look at Brookings: