The Exxon Mobil refinery in Baytown, Texas, in 2008. (Jessica Rinaldi/Reuters)

If you care about free speech, you should pay attention to the campaign now being waged against Exxon Mobil. More than 50 environmental and civil rights groups have written Attorney General Loretta Lynch urging her to open a “federal probe” of the giant energy firm. Bernie Sanders and Hillary Clinton have also joined the chorus. The charge is that Exxon Mobil “systematically misled the public” on climate change, even as its executives recognized the dangers. New York’s attorney general has already launched an investigation.

What’s behind the latest assault are two recent pieces of investigative journalism that, based on company documents, concluded that Exxon Mobil played a double game. In the 1970s, when global warming began attracting scientific attention, the firm “assembled a brain trust [that deepened] the company’s understanding” of climate change, reported InsideClimate News. But in the late 1980s, the company switched to “climate denial,” manufacturing “doubt about . . . global warming its own scientists” had confirmed. Stories in the Los Angeles Times told a similar tale.

Not so, responds Exxon Mobil (unsurprisingly). The investigative pieces “cherry-pick” their evidence, exaggerating the divide between the company’s scientists and corporate policy, says Ken Cohen, vice president of public and government affairs.

As an example, he cites a scientific presentation made to Exxon’s board of directors in early 1989 concluding that global warming is, in the briefing’s words, “deeply imbedded in scientific uncertainty . . . [and] will require substantial additional investigation.” Instead, Cohen asserts, the Los Angeles Times portrayed the presentation as demonstrating that the enormity of global warming was settled.

Nor, he says, does Exxon Mobil oppose all action against climate change. Since 2009, it has endorsed a carbon tax, a position shared by many environmentalists and economists. Taxing the carbon in fossil fuels — oil, coal, natural gas — would raise their prices. That would, at least in theory, encourage energy efficiency and switching to non-fossil fuels. (Exxon Mobil prefers a carbon tax to a cap-and-trade system, which it argues is harder to administer. Many economists agree.)

The feuding between Exxon Mobil and environmentalists is long-standing. In a 2007 report, the Union of Concerned Scientists (UCS) accused the company of financing “a sophisticated disinformation campaign . . . to deceive the public” about global warming. From 1998 to 2005, the UCS said, Exxon Mobil gave $16 million to 43 groups that preached climate change skepticism. (The company says it has since halted many of these grants.)

For many environmentalists, it’s gospel that Exxon Mobil’s campaign stymied remedial policies. Americans were unsure of global warming’s reality. “We’ve had 20 years of delay because of the doubt and confusion sowed by Exxon Mobil and [climate] deniers,” says Eric Pooley of the Environmental Defense Fund.

This is questionable. For starters, millions of Americans revile big oil companies; they’re not uncritical consumers of industry propaganda. The larger problem is the inherent difficulty of doing something significant about global warming. Fossil fuels supply four-fifths of primary global energy. To stabilize atmospheric greenhouse gas concentrations, fossil fuel emissions need to go to about zero. How is that going to happen?

There’s no obvious answer, and any interim steps — whether a carbon tax or cap-and-trade — would increase fuel prices. That’s a hard sell for politicians and the public. Our political system is simply not good at inflicting present pain for uncertain future gains. (For proof, see budget deficits.) Moreover, progress in the United States and other wealthy countries would need to be matched in China, India and other developing countries whose energy appetite is still increasing.

To crystallize this complex problem into a conspiracy controlled by Exxon Mobil is to engage in political make-believe. This is a dangerous and self-serving exercise that brings us back to free speech. Genuinely free speech transcends accepted and respected beliefs. It includes viewpoints that are wrong, offensive and ignorant. We take pride in the marketplace of ideas — a dividend of free speech — to sort the worthy from the unworthy. If government assumes that function, you no longer have free speech.

The advocates of a probe into Exxon Mobil are essentially proposing that the company be punished for expressing its opinions. These opinions may be smart or stupid, constructive or destructive, sensible or self-interested. Whatever, they deserve protection. An investigation would, at the least, constitute a form of harassment that would warn other companies to be circumspect in airing their views. Matters could be worse if the government somehow imposes monetary penalties or opens the floodgates to suits by plaintiffs’ attorneys, a la the tobacco industry. Significantly, the letter to Attorney General Lynch does not allege any violation of law.

Exxon Mobil (2014 earnings: $32.5 billion) does not command our sympathy. But free speech does not belong only to the sympathetic. Casting Exxon Mobil as the scapegoat for global warming’s dilemmas is historically inaccurate and a political cheap shot with troubling constitutional implications.

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