The First Amendment provides robust protection for political and scientific debate, but it faces a new threat from a climate activist determined to silence his critics. In a case pending before the District of Columbia Court of Appeals, Penn State professor Michael Mann is waging an aggressive campaign of lawfare, accusing of defamation those who dare to question his work. So far, the courts have given this assault on free speech a green light.
Mr. Mann is famous as the creator of the “hockey stick” graph, which portrays a dramatic trend in global warming over the past century. Numerous critics have cast doubt on the quality and accuracy of his work. They argue that his historical temperature proxies are unreliable, his data presentation misleading, and his statistical techniques skewed.
Even among those who support the theory of global warming, some have singled out Mr. Mann’s work as sloppy and exaggerated. David Hand, a former president of Britain’s Royal Statistical Society, has written that Mr. Mann’s technique “exaggerated the size of the blade at the end of the hockey stick,” which corresponds to the 20th-century temperature rise.
Not content to answer his critics in the public square, Mr. Mann has sued them. One target of his lawsuit is the political magazine National Review, which published a 270-word blog post criticizing Mr. Mann as “the man behind the fraudulent . . . ‘hockey-stick’ graph.” His lawsuit objects to the magazine’s decision to quote a critic who wrote that Mr. Mann “could be said to be the Jerry Sandusky of climate science, except that instead of molesting children, he has molested and tortured data.”
National Review moved to dismiss the suit, citing a phalanx of Supreme Court precedent. The Constitution obviously does not allow crippling damages to be imposed for voicing one’s opinion, however vehemently or caustically. Punishing such criticism because a jury disagrees with it does not aid the search for truth, but impedes it by stifling conflicting views. As the liberal Justice William Brennan observed: “Truth may not be the subject of either civil or criminal sanctions where discussion of public affairs is concerned.” Such speech “is the essence of self-government.”
As a federal court once put it in the particular context of scientific controversies: “More papers, more discussions, better data, and more satisfactory models—not larger awards of damages—mark the path toward superior understanding of the world around us.” Even a meritless defamation suit can be an effective weapon to intimidate critics and shut down debate through ruinous litigation costs.
