Remember when climate change could be a bipartisan issue? Newt Gingrich and Nancy Pelosi did an advertisement together, boasting of their partnership on the challenge it posed. John McCain also believed that man-made climate change was an urgent problem. Now it’s virtually impossible to find any leading Republicans, including potential Presidential candidates, who will agree, without equivocation, on all of these points: that temperatures are rising, that human beings caused it, and that the nation and the world must take action to address it.

Republicans are unified in denial, and one good reason this is so is the Supreme Court’s decision in the Citizens United case. That decision revolutionized the law of campaign finance; what is less well recognized is that it transformed the climate-change debate, too. Justice Anthony Kennedy’s majority opinion in Citizens United, in 2010-the Justices were divided 5-4-began the Super PAC era in American politics. At the time, the decision was most remarked upon for its assertion that corporations possessed a right to freedom of speech, under the First Amendment, much as individuals do. In fact, this part of the case was neither new nor particularly controversial. (Courts have granted corporations, like newspapers, First Amendment records for decades.) […]