The concept of the think tank is elastic. Some maintain a strict independence; others are purely ideological. Some like to collaborate with the state; others shun it. Some occupy a niche; others are generalist. Some allow research and facts to speak; for others, ideas and principles are crucial.

Even if lobbyists work for special interests, and grassroots organisations base their work on member activism, the difference between them and think tanks is diffuse. Political and financial independence and the connection to research, the two factors that make their position special, are far from self-evident lines of demarcation.

In practice, the boundaries are fluid. Lobbyists and grassroots organisations provide politicians with advice and information based on facts. Think tanks of a more ideological kind, with their closeness to politicians, are closer to lobbying.

"This is because of our political system, which is porous and difficult to control. No player can d...