Rep. Lamar Smith argued on Wednesday that not only does his House Science committee have the authority to subpoena two state attorneys general investigating ExxonMobil, but a constitutional obligation to ensure that science isn’t being undermined by such investigations.

But while the committee hearing was ostensibly to address the constitutional issues of Smith’s subpoenas, it served as a showcase for scholarly disagreements and political divides.

Looming over the 2½-hour hearing were the questions of whether the committee was abusing its oversight authority to defend the oil and gas industry—and Exxon—against legitimate probes by New York’s Eric Schneiderman and Massachusetts’ Maura Healey, or whether it was standing up to attempts to suppress dissenting views on climate change.

The genesis of the hearing was the refusal by the two attorneys general to comply with Smith’s subpoenas seeking information on their ongoing investigations into whether Exxon misled investors on climate change.

“The documents demanded will allow the committee to assess the breadth and depth of the AG’s investigations and inform our understanding of whether their actions have a chilling impact on scientific research and development,” Smith said in his opening remarks.

“The question we explore today isn’t partisan, it’s institutional. Allowing subpoenaed parties to ignore compliance based on the politics of the subject sets a dangerous precedent.”

Eddie Bernice Johnson, the ranking Democrat on the committee, called the hearing politically motivated and designed to advance the agenda of the fossil fuel industry.

“The Majority has claimed that their investigation is about protecting the First Amendment rights of ExxonMobil,” Johnson said.

“However, the law is clear: fraud is not protected by the First Amendment. If any companies in the oil industry defrauded the public or their shareholders in their well-documented disinformation campaign on global warming, then that is a matter for the state AGs and the courts, not the Committee on Science.”

One of Rotunda’s examples of the “chilling effect” that the state investigations might exacerbate concerned Harvard University geophysicist Jerry Mitrovica’s research on the sea-level effects of the rebound in elevation in Greenland following the melting of the Greenland Ice Sheet. Rotunda claimed that Mitrovica’s research shows the effect would be a lowering of sea levels, which, Rotunda further claimed, clashes uncomfortably with scientific orthodoxy causing Mitrovica to favor research on climate change in the geologic record rather than in the present. The example raised the suspicion of Rep. Bill Foster (D-IL), a professional physicist, who quizzed Rotunda on the matter.

Contacted for comment, Mitrovica himself confirmed that Rotunda’s testimony “completely misrepresents” his research, which anticipates higher than predicted sea level rises across much of the globe. Mitrovica also described Rotunda’s linking of his views on the politics of climate change research to the ExxonMobil investigations to be “about as despicable a misrepresentation of my views that I have ever read or heard.” Mitrovica noted that his complaints revolve around the actions of “climate change skeptics who respond to rigorous scientific work with dismissiveness, insults, and hostility.”

In 2000, Rotunda was a visiting legal scholar at the Cato Institute, a think tank co-founded by oil and gas billionaire Charles Koch that is heavily funded by the Koch brothers.

Currently, Rotunda is a Policy Expert at the Heartland Institute, which describes itself as “the marketing arm of the free market movement,” but is most well known for its decades of climate change denial. A vocal critic of renewable energy and a cheerleader for fossil fuels, the Heartland Institute is notoriously secretive about its donors.

But many of the organization’s largest known donors are fossil fuel industry companies and organizations with direct ties to the oil and gas industry.

Heartland has received at least $676,500 directly from Exxon since 1998, including $140,000 in grants that were earmarked for climate change work. It has received hundreds of thousands from various branches of the Koch brothers’ donor networks, through family foundations and directly from Koch Industries. Heartland has also received more than $17.5 million in anonymous money through Donors Capital Fund and more than $600,000 from Donors Trust including numerous grants with climate related titles.

Donors Trust and Donors Capital Fund are dark money organizations that allow donors to give privately, and are known to receive millions from the Koch brothers’ various entities.

Rotunda has recently criticized the state AGs for using their unquestionably legal subpoena power to request records from Exxon. Rotunda wrote for the Verdict blog and Heartland Institute’s blog, “The marketplace of ideas, not the subpoena power of government, should decide what is true or false.” However, at the September 14 hearing, he is expected to argue for a Congressional subpoena power that critics argue is without precedent.