Throughout the long campaign, and in the long month that has followed, President-elect Donald Trump sounded some odd notes about the environment.

He rejected the scientific fact of climate change, calling it a hoax or a fraud. He repeatedly announced his intent to repeal all of the Obama administration’s environmental regulations. He lamented, wrongly, that you couldn’t use hairspray anymore because it damaged the ozone layer.

And then, out of nowhere, he met with Al Gore, who won a Nobel Peace Prize for educating the public about the dangers of climate change.

While the broad strokes of Trump’s policies were never in doubt, there was often enough bizarreness to wonder what he would do with the powers of the Environmental Protection Agency.

On Wednesday, those questions were all but settled. Trump has chosen E. Scott Pruitt, the attorney general of Oklahoma, to lead the EPA, according to early reports.

In a certain light, Pruitt is an inspired choice to lead the EPA, as he has made fighting the agency a hallmark of his career. His own website calls him “a leading advocate against the EPA’s activist agenda.” The significance could not be more clear: As he promised on the trail, Trump will likely use the powers of the presidency and the legal expertise of Pruitt to block or weaken the Obama administration’s attempts to fight climate change.

And Trump will be able to try for more than that. For what distinguishes Pruitt’s career is not just his opposition to using regulation to tackle climate change, but his opposition to using regulation to tackle any environmental problem at all. Since he was elected Oklahoma’s attorney general, in 2010, Pruitt has racked up a sizable record—impressive in its number of lawsuits if not in its number of victories—of suing the EPA.

Many of these suits did not target climate-related policies. Instead, they singled out anti-pollution measures, initiated under previous presidential administrations, that tend to be popular with the public.

In 2014, for instance, Pruitt sued to block the EPA’s Regional Haze Rule. The rule is built on a 15-year-old program meant to ensure that air around national parks is especially clear. Pruitt lost his case.

Last year, he sued to block a rule restricting how much mercury could be emitted into the air by coal plants. He lost that, too.

And early in his tenure, he sued to keep the EPA from settling lawsuits brought by environmental groups like the Sierra Club. That one was dismissed.

He has brought other suits against EPA anti-pollution programs—like one against new rules meant to reduce the amount of ozone in the air—that haven’t been heard in court yet. While ozone is beneficial to humans high in the atmosphere, it can be intensely damaging when it accumulates at ground level, worsening asthma and inducing premature deaths. The American Lung Association calls it “one of the most dangerous” pollutants in the United States.

All this is not to say that Pruitt has omitted climate regulations from his litigation. His most common target has been the Clean Power Plan, the Obama administration’s set of Clean Air Act rules meant to reduce greenhouse gas emissions from power plants. The Clean Power Plan is Obama’s main mechanism for pushing the United States to meet its pledge under the Paris Agreement.

Pruitt began suing the EPA to block the Clean Power Plan more than two years ago. Now, Oklahoma is one of the 28 states challenging the agency in court, and it helped succeed in getting the Supreme Court to block the rules in February.

As I wrote in September, there are valid legal reasons that lawmakers might oppose aspects of the Clean Power Plan. Lawrence Tribe, President Obama’s old law-school mentor, argued in court that he believes some of its provisions go too far in asserting federal power. A cap-and-trade component is particularly controversial.

But Pruitt’s understanding of the bill seems not entirely legally minded in two significant ways. First, Pruitt’s knowledge of global warming appears lacking, at best. Earlier this year, for instance, he wrote in the National Review that “scientists continue to disagree about the degree and extent of global warming and its connection to the actions of mankind.”

While this sounds reasonable, it is not true. The overwhelming consensus among scientists who study the Earth is that humans are largely to blame for the planet’s warming. Climate scientists have understood this to be the case since at least the early 1990s, and since then scholarly consensus on the issue has only strengthened. The majority of scientists also believe that global warming will be quite harmful; the scientific debate about its “degree and extent” is only about how bad it will be and how soon its consequences will kick in.

Second, Pruitt has worked extremely closely with oil and gas companies in opposing the plan. In one case, a New York Times investigation revealed that Pruitt sent an official letter to the EPA, bearing his signature and letterhead, that had been almost completely written by lawyers at Devon Energy, a major oil and gas company. It was delivered to Pruitt’s office by Devon’s chief lobbyist.

Energy firms and lobbyists, including Devon, have donated generously to the Republican Attorneys General Association, which Pruitt has led. In interviews after the Times report, Pruitt described the collaboration as a kind of constituent service, saying that Devon is based in Oklahoma City. He agreed with the letter’s legal reasoning, he said, so he signed it.

“I don’t think there is anything secretive in what we’ve done,” Pruitt told The Oklahoman. “We’ve been very open about the efforts of my office in responding to federal overreach.”

Now Pruitt could be the one doing the federal reaching. Environmental groups immediately condemned Trump’s selection of him. “The EPA plays an absolutely vital role in enforcing long-standing policies that protect the health and safety of Americans, based on the best available science,” said Ken Kimmell, president of the Union of Concerned Scientists, in a statement. “Pruitt has a clear record of hostility to the EPA’s mission, and he is a completely inappropriate choice to lead it.”

More unusually, New York state’s attorney general also decried the choice. “As attorney general, Scott Pruitt consistently failed to uphold his responsibility to protect our nation’s air and water, instead acting as an agent of the oil and gas industry—at the expense of the American people—every time,” said Eric Schneiderman in a statement.

The statement wasn’t totally out of the blue, as Schneiderman and Pruitt have clashed before. In March, Pruitt alleged that Schneiderman was stifling debate when he investigated whether Exxon was properly communicating the business risks of climate change to its investors. They’ll likely also clash again: As the powerful attorney general of a populous liberal state, Schneiderman will lead the litigative charge against any weakening of EPA regulations—just as Pruitt led litigation against Obama’s EPA.

Every Republican administration since Ronald Reagan’s has taken office promising to roll back some environmental regulations. Many have succeeded in part. But most Americans like strict environmental regulations, and both the Reagan and Bush White Houses discovered that relaxing limits on pollution is particularly unpopular.

Once, it had seemed like perhaps Trump—who speaks often of his adoration for clean air and clean water—would bypass those old fights and only target Obama’s new climate rules. But with Pruitt leading his EPA, it seems that Trump’s administration will act like its GOP predecessors. Whether it is successful will depend on the Senate, on the courts, and on how well environmental advocates make their case to the public.