As part of a growing trend of lawsuits over climate change impacts, cities and states across the U.S. are seeking damages from oil, gas, and coal companies whose products drive the crisis and which for years evidently engaged in disinformation and denial campaigns to stall climate action.

Now the fossil fuel industry is pushing back, taking a page out of Big Tobacco’s playbook to rein in that liability litigation, and getting help from an unexpected source.

Behind the scenes, politically affiliated groups are quietly providing support. One of the outfits promoting the efforts to counter the slew of climate lawsuits is none other than the Progressive Policy Institute (PPI), a center-left Washington, D.C.-based think tank with links to the Democratic party.