The writers, both Democrats, represent Rhode Island and Massachusetts, respectively, in the U.S. Senate.

For years, ExxonMobil actively advanced the notion that its products had little or no impact on the Earth’s environment. As recently as last year, it continued to fund organizations that play down the risks of carbon pollution. So what did ExxonMobil actually know about climate change? And when did it know it?

Reasonable questions — particularly if ExxonMobil misled its investors about the long-term prospects of its business model or if the company fooled consumers into buying its products based on false claims.

So now the attorneys general of Massachusetts and New York are investigating whether ExxonMobil violated state laws by knowingly misleading their residents and shareholders about climate change. Those investigations may be making ExxonMobil executives nervous, and their Republican friends in Congress are riding to the rescue. House Science, Space and Technology Committee Chairman Lamar Smith (R-Tex.) and his fellow committee Republicans have issued subpoenas demanding that the state officials fork over all materials relating to their investigations. They also targeted eight organizations, including the Union of Concerned Scientists, the Rockefeller Family Fund and Greenpeace, with similar subpoenas, demanding that they turn over internal communications related to what Smith describes as part of “coordinated efforts” to deprive ExxonMobil of its First Amendment rights.

Take a breath to absorb that: State attorneys general are investigating whether a fraud had been committed — something state AGs do every day. Sometimes AGs uncover fraud and sometimes they don’t, but if the evidence warrants it, the question of fraud will be resolved in open court, with all the evidence on public display. But instead of applauding the AGs for doing their jobs, this particular investigation against this particular oil company has brought down the wrath of congressional Republicans — and a swift effort to shut down the investigation before any evidence becomes public. So far, both AGs and all eight organizations have refused to comply. We say, good for them.

Let’s call this what it is: a master class in how big corporations rig the system. According to the Center for Responsive Politics, Smith has received nearly $685,000 in campaign contributions from the oil and gas industry during his career. Now he is using his committee to harass the investigators and bully those who dare bring facts of possible corporate malfeasance to their attention. Undoubtedly, the oil industry wants no further attention, much less court-supervised discovery, into whether it has spent decades deliberately deceiving the public about the harms associated with its product. So here come Smith and his Republican colleagues with threats of legal action designed to sidetrack state investigations and silence groups petitioning the government to address potential wrongdoing.

There’s plenty for the AGs to investigate. The Union of Concerned Scientists, for example, issued a 2015 report, “Climate Deception Dossiers: Internal Fossil Fuel Industry Memos Reveal Decades of Corporate Disinformation,” and a 2007 report, “Smoke, Mirrors & Hot Air: How ExxonMobil Uses Big Tobacco’s Tactics to Manufacture Uncertainty on Climate Science.” Both reports document how the industry has protected its bottom line by funding front organizations and scientists to put out junk science contradicting what peer-reviewed scientists, and even the industry’s own experts, were saying about how its products affected the environment. Union of Concerned Scientists President Ken Kimmell rightly dismissed the committee’s request, saying, “Mr. Smith makes no allegation that UCS violated any laws or regulations, and his claim, that providing information to attorneys general infringes on ExxonMobil’s rights, is nonsense.”

Massachusetts Attorney General Maura Healey and New York Attorney General Eric Schneiderman are also fighting back. In separate letters, they told Smith that they have no intention of complying with the committee’s request. “The Subpoena brings us one step closer to a protracted, unnecessary legal confrontation which will only distract and detract from the work of our respective offices,” Schneiderman wrote.

Smith is not the first fossil-fuel-backed Republican in Congress to come to the industry’s defense. In May, Senate Environment and Public Works Committee Chairman Jim Inhofe (R-Okla.), recipient of $1.8 million in oil and gas industry contributions since 1989, called the state AGs’ investigation a “misuse of power” and “politics at its worst.” The greater abuse comes when congressional committees appear to operate at the behest of the industries they are meant to oversee.

Congressional investigations and hearings have a unique ability to focus a nation’s attention and bring facts of public importance to light. As committee chairmen, Smith and Inhofe can direct their committees’ authority as they see fit, but using that power to stifle lawful state investigations doesn’t advance the First Amendment, it tramples on it.

So we have an alternative suggestion. If Chairmen Smith and Inhofe are concerned about the First Amendment rights of ExxonMobil, they should each call a hearing, ask ExxonMobil executives to testify, and give them the opportunity to set the record straight. A committee chairman could do little more to protect any person’s right to speak freely than to give that person the chance to testify before Congress. We would love to hear what they have to say.