President Donald Trump vowed to gut the Environmental Protection Agency , and the Senate has just confirmed his man to do it.

Scott Pruitt, who was sworn in as EPA administrator early Friday evening, will wield vast power to reshape the 46-year-old, 15,000-person agency he has criticized so fiercely.


As Oklahoma's attorney general, Pruitt sued the agency at least 14 times — often in lockstep with fossil fuel companies — to try to overturn the agency's air and water regulations. He has questioned the role of humans play in climate change, while arguing that much of the agency's authority should be in the states' hands.

Now, Pruitt's actions — and the executive orders Trump is planning for the agency — could have repercussions for years.

“Most of the business community really is looking to Pruitt to make changes that will be enduring — not to do things that can easily be undone by the next administration, but really sensible things,” said Jeffrey Holmstead, a top EPA official in George W. Bush’s administration who is now at Bracewell LLP.

Here’s POLITICO’s guide to what to watch as Trump and Pruitt move to rein in the EPA, even as environmentalists plan to battle them in Congress and the courts:

1. Climate change: Trump and Pruitt have vowed to dramatically shift course on the Obama administration’s landmark climate change efforts. The president has threatened to pull out of the 2015 Paris climate deal, in which the U.S. and nearly 200 other nations agreed to make sharp cuts in their greenhouse gas output. And EPA’s Clean Power Plan, which requires cuts in the power industry’s carbon dioxide emissions, has a target on its back.

Pruitt is expected to swiftly begin the years -long process of repeal ing the Clean Power Plan. But an appellate court is set to rule on that regulation any day now, and it’s not clear that the judges would allow him to undo the rule right away. Moreover, any effort by Pruitt to undercut the regulation would have an easier time if the courts strike it down first. That legal fight probably won't be over until it reaches the Supreme Court.

But even if the Trump administration succeeds in killing the Clean Power Plan, Pruitt will still be on the hook to regulate carbon dioxide emissions because of the so-called endangerment finding — EPA's 2009 scientific conclusion that climate change threatens human health and welfare. Trump promised on the campaign trail to review and possibly revoke that finding, although Pruitt rejected that idea during his confirmation hearing.

“The endangerment finding is there and needs to be enforced and respected,” Pruitt told members of the Senate Environment and Public Works Committee. “There is nothing that I know that would cause a review at this point.”

2. Water protections: After years of legal confusion about which streams and wetlands deserve protection under the Clean Water Act, the Obama administration issued a landmark regulation in 2015 to cover head -water streams and some wetlands and ponds. Called the Waters of the U.S. rule, or WOTUS, the regulation sparked a fierce backlash from homebuilders, farmers and the oil and gas industry, which say it gives the federal government vast power over everything from stock ponds to puddles, and Trump has vowed to kill it.

Working in Trump's favor is th e fact that the legal battle over the WOTUS rule isn’t as far along as the fight over the Clean Power Plan, so the administration may simply ask the courts to let it take another stab at crafting the regulation. Pruitt told lawmakers he would seek to rewrite it, although he also said he’d welcome a move by Congress to more clearly define where the line should be drawn — something lawmakers have failed to reach consensus on after nearly a decade of trying.

If Pruitt’s agency takes another stab at the water rule, expect it to sharply shrink the number of tributaries and wetlands that warrant federal protection. While environmental groups would oppose such efforts, sportsmen’s groups may be the political players to watch. Hunting and fishing groups care about the headwaters streams that are home to trout and other fish, and have prove d to have pull with the Trump administration.

3. Executive orders: Trump is widely expected to sign one or more executive orders shortly after Pruitt takes the helm at the agency, setting the priorities and tone for his EPA. Top targets for the orders could include the agency’s climate change work, its broad enforcement powers or its overall approach to regulation.

Of course, executive orders are tied to the president who signs them, and the next administration can quickly undo them. But orders can also be used to set in motion a broader set of changes that aren’t as easily wiped out. For instance, industry groups have long urged EPA to change the way it measures the costs of new regulations, something that could significantly alter the labyrinthine regulatory review process for years. And businesses have sought to install experts more attuned to economic impacts on the agency’s advisory panels.

“If EPA were to expand that and appoint people who have a different way of looking at things, I think it would be hard to put back in the bottle,” Holmstead said.

4. Personnel: One early Trump adviser on the EPA, the fierce agency critic Myron Ebell, had a clear recommendation for reining it in: Slash the workforce.

His call to cut EPA’s staff by two-thirds got a lot of media attention but would be virtually impossible to accomplish, and the Trump administration has distanced itself from that recommendation. Still, attrition can pack a punch, especially when a number of employees are nearing retirement age and the promise of an unfriendly leader has sent morale plunging.

Even the temporary across-the-board federal hiring freeze in place now is having an impact. Catherine McCabe, who has served as acting EPA administrator for the past month, said last week that “the freeze on hiring is already creating some challenges to our ability to get the agency's work done,” in a video posted to the agency’s YouTube channel.

Environmentalists fear that effects on staffing under the Trump administration could be one of the blows to the agency that’s hardest to recover from.

“To get the experience, to get the staffing, to get the institutional knowledge — those are the kinds of things that happen sometimes below the radar screen, but can have a long-lasting effect,” said David Goldston, director of government affairs for the Natural Resources Defense Council.

5. Legislation: Truly lasting changes in the country’s approach to environmental regulation will require action by Congress. And after eight years of having their efforts met with veto threats from the White House, Republicans on Capitol Hill now see an opening.

But any such legislation will face a 60-vote threshold in the Senate, so a wholesale revamp that many in the GOP want to see is likely to remain out of reach.

Key Republican leaders have said they plan to take a rifle-shot approach to the Clean Air Act, and they may try again to influence the reach of the Clean Water Act. But even with a number of moderate Democrats facing reelection in 2018, it’s not clear that they’ll have the votes to get it through.

However, having Pruitt in place may reduce the intensity of annual appropriations battles, where Republicans in prior years have tried to use EPA spending bills to block implementation of key Obama administration rules. Sen. Lisa Murkowski (R-Alaska), who chairs the Appropriations subcommittee with jurisdiction over the agency, said she did not expect to push riders blocking things like the WOTUS rule or Clean Power Plan because the Trump administration will already be working to reverse those.

“So , some of those that were pretty high-profile last year, I think we can say, ‘OK don’t need to worry about those,’” Murkowski told POLITICO.