“Merchants of Doubt” links cigarettes and climate — with a fascinating and troubling detour into an investigation by The Chicago Tribune of the flame-retardant industry — by noting that both the playbook and many of the players are the same. “I’m not a scientist,” a recently adopted catchphrase among Republican politicians, echoes earlier evocations of complication and confusion. In both cases the science could hardly be clearer, but pseudo-experts can be brought before the cameras to peddle the idea that no real consensus exists. False information need not be coherent to be effective, and the specters of vanished liberty and tyrannical government regulation are easy enough to conjure.

Image “Merchants of Doubt” includes, clockwise from top, Marc Morano, a skeptic of climate change; Bob Inglis, a former Republican congressman; and the scientist James E. Hansen.

And science can be tricky to explain and to defend, especially in the shouting-heads cable news format. The scientists Mr. Kenner interviews — notably James E. Hansen, formerly of NASA, who was among the first to establish a link between carbon emissions and climate change — tend to be earnest and serious. The scientific method is also predicated on intellectual humility, on falsifiable hypotheses and endless revisions in the face of new data. Public relations, in contrast, is built on slickness, grandiosity and charm. These traits are exemplified by Marc Morano, a cheerful and unapologetic promoter of climate-change skepticism and currently the executive director of the website Climate Depot.

One of the film’s conceits is that the actions of Mr. Morano and his colleagues can be con games and magic tricks. A professional magician, Jamy Ian Swiss, is on hand to fool an audience with a deck of cards and to draw a distinction between his own “honest lies” and the shady doings of corporate shills and spinners. But his presence, and the animated playing cards that sometimes fly across the screen, feel like a glib and somewhat condescending gimmick, an attempt to wring some fun out of a grim and appalling story.

More than that, the analogy between climate-change denial and classic confidence schemes doesn’t really hold up. Since the ’80s and ’90s, when the tobacco industry was trying to slow down regulation and lawsuits, the political landscape has changed, and so have the techniques of the anti-science side. Some of the attorneys general who forced the 1998 settlement were Republicans, after all. By contrast, in 2010 Bob Inglis, a conservative Republican congressman from South Carolina, was defeated in the primary after publicly acknowledging the reality of climate change.

Climate-change denial has been raised to an ideological principle, a tenet of modern conservative and libertarian politics. Deceit and secrecy are hardly necessary when large portions of the public eagerly accept the message. If anti-environmentalist politics resemble a game of three-card monte, it’s one in which all the cards are face up and the marks place their bets on a nonexistent ace. Anyone who points out the error can be accused of liberal bias, and credulous journalists will give equal weight to both sides of the “debate.”