Is Exxon-Mobil a criminal organization?  The attorneys general (AGs) of New York and Massachusetts apparently think so.  These AGs may also believe that engaging in public discourse on this very significant policy issue is criminal.

Sixteen democratic AGs announced a joint investigation of Exxon this past March.  The allegations involve Exxon’s denial of the consequences of global warming and opposition to the Obama administration’s climate change policies.  The AGs have also left open the door to legal action against others delaying action on climate change.

The legal basis of the Exxon probe is inadequate disclosure of the risks of global warming in reports to stockholders.  Corporations issue annual reports for their stockholders explaining the current condition and future outlook for the company, including future risks.  So for instance, a corporation will disclose pending lawsuits against it, as well as an estimate of how much the claims might eventually cost.

As part of the investigation, a dozen policy organizations, including the Competitive Enterprise Institute (CEI) and the Heartland Institute, were subpoenaed for correspondence with Exxon going back to at least 1997.  CEI and Heartland have argued against aggressive policy action to combat global warming.  (For full disclosure, I once wrote a policy study for CEI on global warming and the costs of hurricanes.)

The AGs have offered a parallel to tobacco companies’ hiding evidence on the risks of smoking.  But the cases differ significantly.  Tobacco companies conducted and withheld research studies showing the risks of smoking, while publicly denying the health risks in spite of the evidence.  Adequate disclosure in their annual reports was secondary – the real offense was withholding evidence.

Alex Esptein of the Center for Industrial Progress (one of the subpoenaed organizations), author of the excellent book The Moral Case for Fossil Fuels, has pointed out how global warming differs.  Persons labelled “climate change deniers” argue using government data and papers published in academic journals.  Mr. Epstein, CEI, and others simply draw different conclusions from the data and studies used by the Intergovernmental Panel on Climate Change (IPCC).  Exxon is not sitting on studies “proving” the validity of human-caused warming.

President Obama often cites a 97% scientific consensus on global warming, so is there really a valid debate?  I am an economist, so my opinion on the climate science underlying global warming doesn’t really matter.  Surveys touting the 97% claim typically ask a very narrow question about whether warming is occurring and humans are contributing.  This is not in doubt.  The case for aggressive policy action depends entirely on how much warming will occur and how costly it might prove.

These questions are reasonably debatable.  Satellites provide the most accurate measurement of the Earth’s temperature, and show an increase in global temperatures since the start of these records in 1979.  But the increase since 1990, the date of the first IPCC report, has been less than half of that predicted by leading climate models.  A 2015 paper in the Scientific Bulletin argues that the climate models may run hot because they were built from engineering models including positive feedback loops, or in other words, may be a feature of the models, not the world.  And the appropriate response to warming would involve economic factors beyond the scope of climate science.

I think that the Democratic AGs are essentially threatening prosecution of opponents of the Obama administration’s climate change policies.  The Democratic AGs have been called out on this by some of their fellow AGs for this.  Thirteen AGs, led by Alabama’s Luther Strange, released a letter in June noting the “substantial First Amendment concerns” raised by a prosecution on a policy issue on which “a vigorous debate exists in this country.”

Appreciation of the importance of freedom of speech in the search for truth goes back to at least John Milton and John Stuart Mill.  Our democracy is based on citizens’ freedom to campaign against current office holders and their policies in the next election.  Global warming skeptics may be wrong.  The proper response to an incorrect argument, however, is a better argument, not subpoenas and threats of criminal prosecution.

Daniel Sutter is the Charles G. Koch Professor of Economics with the Manuel H. Johnson Center for Political Economy at Troy University and host of Econversations on TrojanVision.  The opinions expressed in this column are the author’s alone and do not necessarily reflect the views of Troy University.