The Koch team by then could count on its Club for Growth to fund primary challenges to ensure that the party line on environmentalism would be maintained by Republican members of Congress. That explains why Senator John McCain is but the best-known—and once most principled—Republican to flip his position after being faced with a Tea Party primary challenge. By 2014, only 8 of 278 Republicans in Congress were willing to acknowledge that man-made climate change is real.31
