If you’re like me,
paranoid, mistrustful of authority, suspicious curious about where these “public interest groups” get their money, here’s a useful website. Of course, they have their own agenda, but it’s at least a place to kick off your research.
(I used to have a link to a web site that had the required public filings from 501(3)(c) nonprofits online. Anyone out there know what site that is?)