Nearly a dozen GOP attorneys general (AG) have called for an investigation into ExxonMobil Corp. research about the effects of fossil fuel production on climate change to be dismissed, claiming the probe by two Democratic colleagues is unconstitutional.

An amicus brief filed in U.S. District Court for the Southern District of New York in Manhattan supports a lawsuit by ExxonMobil to dismiss a wide-ranging probe by New York’s Eric Schneiderman and Maura Healey of Massachusetts, both Democrats. The brief was signed by the top prosecutors of Alabama, Arizona, Arkansas, Louisiana, Michigan, Nebraska, Oklahoma, South Carolina, Texas, Utah and Wisconsin.

Following months of critical news stories claiming, among other things, that ExxonMobil supposedly violated consumer protection laws by marketing and selling fossil fuel-derived products and securities, Schneiderman in 2015 launched a wide-ranging investigation that has sought internal research and shareholder communications regarding climate change. He has since expanded the probe into ExxonMobil’s reserves reporting. Healey later joined the investigation and issued a civil investigative demand, i.e., a state administrative subpoena.

In the amicus brief in support of ExxonMobil’s attempt to quash the orders, the GOP AGs said Schneiderman and Healey “are not using their power in an impartial manner. Rather, they are embracing one side of a multi-faceted and robust policy debate, and simultaneously seeking to censor opposing viewpoints. This is bad faith.” The two AGs have abused their power and violated ExxonMobil’s rights to free speech by “using law enforcement authority to resolve a public policy debate” about whether carbon emissions contribute to climate change. The questions concerning climate change are not settled, the brief said.

The probe “is the product of a cultural movement…committed to aggressively protecting and building upon the recent progress the United States has made in combating climate change. The common interest agreement of the powers aligned on this axis of ideology underscores the partiality of their endeavor, as they seek to limit climate change and ensure the dissemination of accurate information about climate change…In other words, the defendants’ tactics are part of an aggressive approach to silence dissenting viewpoints by policing the ‘truth’ about climate change in the marketplace of ideas.”

Several of the GOP AGs last year had expressed concerns about the probe, claiming the effort by their colleagues “to police the global warming debate through the power of the subpoena is a grave mistake.” While there is disagreement among the GOP AGs about climate change, they said they “agree on at least one thing — this is not a question for the courts. Using law enforcement authority to resolve a public policy debate undermines the trust invested in our offices and threatens free speech.”

Among other things, the 27-page amicus brief cited an article published in the National Review‘s May 17, 2016 issue, which was written by U.S. Environmental Protection Agency Administrator Scott Pruitt, who at the time was Oklahoma’s top prosecutor. Said Pruitt, “scientists continue to disagree about the degree and extent of global warming and its connection to the actions of mankind.”

The amicus brief noted that many people recognize that “vigorous debate exists in this country regarding the risks of climate change and the appropriate response to those risks. Both sides are well-funded and sophisticated public policy participants. Whatever our country’s response, it will affect people, communities, and businesses that all have a right to participate in this debate.” Schneiderman and Healey should “stop policing viewpoints.”

The amicus brief has “raised important constitutional and legal issues in support of our position that the investigations by New York and Massachusetts are politically based and in bad faith,” said an ExxonMobil spokesman. The investigations are “an attempt to silence political opponents who disagree on the appropriate policies to address climate change.”

A spokeswoman for Schneiderman said the AG planned to “pursue our fraud investigation under New York law, despite attempts by Exxon and Big Oil’s beneficiaries to delay and distract from the serious issues at hand.”

The case is not expected to be resolved anytime soon. Last month ExxonMobil lost its bid to transfer the lawsuit from Manhattan courts to Texas, where it is headquartered.