I’m reading David Brock’s self-expose on the conservative’s efforts to discredit Clinton. He continues to bring up, mention and explain numerous foundations, think tanks, organizations, etc. that are funded by conservative, even far-right wing individuals and groups. The Bradley Foundation, The Heritage Foundation, The Federalist Society, The Project for the Republican Future, The Olin Foundation, Newt Gingrich’s GOPAC, etc. Often, their agendas, as described by Brock, are oppositional, as opposed to theoretical or political. Regardless, it appears that if not a conspiracy, then at least a large, loosely connected network of these groups exists.
I am hoping that this question will not degrade into a debate, which is why I’m posting it here. But - is there a comparable number of liberal or left-wing groups? Is there secret funding for those groups as well? It sounds as if there is a large number of these conservative groups, many of them surreptitiously funded and backed. Is there an equivalent web of these groups on the left?
One theory is that these organizations serve as a counterpoint to academia, which does similar (although ostensibly nonpartisan) research and publication that often supports liberal positions. Thus, it is argued, there is less of a need for independent think tanks on the left. There are some liberal/progressive/left think tanks, for example Urban Institute and Progressive Policy Institute. I would answer your question to say that the left and right both have these organizations, but the right has more of them. Maybe the theory above explains it, or maybe the right just has more money to throw around, or maybe there are other reasons as well.
Of course there are left-wing think tanks. There are think tanks of all hues. See here for some U.K. ones and their interests.