Avid golfers know that when you hit a really awful tee shot, you get to take a Mulligan—a do-over. In the debate over government climate change policy, a typical argument is to claim that there are no Mulligans. For example, the New York Times recently ran a critique of climate scientist John Christy, saying that “if he is wrong, there is no redo.” Naturally, this is supposed to make the reader embrace an interventionist government crackdown on carbon dioxide emissions.