About a week before Donald Trump was sworn in as president, Senator James Mountain Inhofe was preparing to step down as chairman of the Environment and Public Works Committee due to term limits. He released a report listing the committee’s accomplishments, including “disapproving of the president’s carbon regulations,” conveying that “that the science on climate change is not settled,” and joining Instagram. In an accompanying press release, he thanked 28 staffers for their “tireless efforts.” Today, approximately a quarter of those staffers work at the Environmental Protection Agency.

Under Trump, the EPA has become one of the most high-profile arms of the federal government—mostly due to the deregulatory ambition and scandals of its administrator, Scott Pruitt. But Trump didn’t make the EPA that way; Inhofe did. The Oklahoma octogenarian’s fingerprints are on everything from Trump’s selection of Pruitt to lead the agency to the recent confirmation of Deputy Administrator Andrew Wheeler, a former coal lobbyist. Alumni of Inhofe’s office fill the EPA’s top political positions, putting them in charge of implementing an agenda that’s based on an idea that Inhofe helped make mainstream: that environmental scientists, particularly climate scientists, are liars.

If any senator were to have outsized influence at Trump’s EPA, Inhofe would be the logical choice. Both he and Trump have a penchant for conspiracy theories and performative flair. Trump has long believed that human-caused climate change is a “hoax”; Inhofe literally wrote the book on that idea. Inhofe is also well-known for bringing a snowball to the Senate floor in 2015 to try to disprove global warming. “It’s very, very cold out,” he said at the time. “Very unseasonable.” It was February.

Inhofe’s provocative style served a purpose: to push for deregulating air pollutants that cause climate change. Those policies, if not the rhetoric, appealed to many conservatives. “I would credit him as being one of the leaders in looking at things in a different light than some of the environmental groups,” said David Stevenson of the Delaware-based Caesar Rodney Institute. Stevenson was a member of Trump’s EPA transition team, but never met Inhofe, who also served on that team. “He was high on the totem pole,” Stevenson told me. “Most of us were grunts going through the work.”

Several people familiar with the transition suspect that Inhofe played a key role in suggesting Pruitt, a former Oklahoma attorney general, for the role of administrator. “He’s one of my closest personal friends,” Inhofe said of Pruitt in a 2016 interview with E&E News. Inhofe, who is a pilot, said he flew Pruitt around Oklahoma in his plane during Pruitt’s first political race, to “places where my numbers were good. So I’ve been working with him really closely for a long time.” Pruitt has also given money to support Inhofe’s political career through his leadership PAC, Oklahoma Strong Leadership, according to Politico. Today, the two men have nearly identical policy agendas. “[Pruitt’s] been involved in every issue having to do with the EPA that I’ve been involved in,” Inhofe said. Indeed, Pruitt has pursued a policy agenda at EPA that Stevenson said almost exactly mirrors what the transition team wanted: repealing the Clean Power Plan, withdrawing the U.S. from the Paris climate agreement, and reforming the way science can be used at the agency.