U.S. Environmental Protection Agency (EPA) Administrator Scott Pruitt says winning the trust of state-level regulators will be one of his top priorities in the new job.

“I seek to ensure that we engender the trust of those at the state level,” Pruitt said in a speech to EPA employees in Washington, D.C. yesterday. It’s important that states “see us as partners in this very important mission we have as an agency, and not adversaries,” he said.

During the Obama administration, Pruitt emerged as a leading critic of the EPA in his former role as Oklahoma attorney general. He joined with other states, business groups, labor unions and other stakeholders in challenging the Obama EPA in court for overstepping its authority.

Their biggest win was a U.S. Supreme Court stay of the so-called Clean Power Plan (CPP), an EPA regulation that was created after cap-and-trade climate legislation was defeated in Congress in 2010, despite wide Democratic majorities at the time. Like the cap-and-trade bill, the CPP regulation would require states to impose carbon dioxide limits on power plants and mandate the use of more wind, solar and other so-called renewables. In a recent interview with Wall Street Journal columnist Kim Strassel, Pruitt said he now plans to withdraw the CPP.

In his speech to EPA employees, Pruitt pledged that future agency regulations would be “tethered” to existing laws. “The only authority that any agency has in the executive branch is the authority given to it by Congress,” he said.

Pruitt also promised to end abuses of the rulemaking process, such as “regulation through litigation,” in which court settlements between activist groups and regulators are used to provide legal justification for new regulatory mandates. This strategy, which came under fire during the Obama administration, is also known as “sue and settle.”

Pruitt’s nomination was strongly opposed by environmental activist groups like the Sierra Club and NRDC, which were key allies of the Obama administration. In yesterday’s speech, Pruitt may have extended an olive branch to critics by referencing this passage from Sierra Club founder John Muir: “Everyone needs beauty as well as bread, places to play in and pray in where nature may heal and cheer and give strength to body and soul alike.”

But the gesture drew a hostile statement from Sierra Club executive director Michael Brune: “John Muir is rolling over in his grave at the notion of someone as toxic to the environment as Scott Pruitt taking over the EPA.”

For his part, Pruitt said he rejects the idea that economic growth undermines environmental stewardship. “I believe that we as an agency and we as a nation can be both pro-energy and jobs and pro-environment,” he said.

Pruitt also defended the nation’s record on the environment. “I think our nation has done better than any nation in the world in making sure we do the job of protecting our natural resources and protecting our environment, while also respecting the economic growth and jobs our nation seeks,” he said.