Until Judge Merrick B. Garland is confirmed as attorney general, Monty Wilkinson, a longtime career employee who worked closely with Eric H. Holder Jr. when he was attorney general, is serving in an acting capacity.
The acting deputy attorney general is John P. Carlin, who ran the national security division of the Justice Department during the Obama administration. He is holding the office only until Lisa Monaco, who has worked closely with Mr. Carlin over the years, can be confirmed as deputy attorney general. She served as homeland security adviser under Mr. Obama and, during the Trump years, she and Mr. Carlin ran a group studying the hardest issues in cyberpolicy.
Much as the politicization of the Justice Department angered Mr. Trump’s critics, the neutering of the Environmental Protection Agency prompted outrage from progressives, and it is probably no surprise that the agency is already in the throes of transformation.
About a month before Inauguration Day, a Trump official who ran the water office, Charlotte Bertrand, suddenly emerged as the woman who would take over as acting administrator if the head of the agency resigned. When that moment came, she never had a chance to settle into the chair.
Just hours into his presidency, Mr. Biden named Jane Nishida, the agency’s principal deputy assistant head of the Office of International and Tribal Affairs, to lead the agency until his nominee, Michael S. Regan, North Carolina’s top environmental regulator, is confirmed.
But long before Mr. Regan gets to the building, a cadre of young staff members — a roster that reads like a who’s who of climate change policy wonks, many of them culled from the Obama administration — will be at work.
Tiernan Sittenfeld, the senior vice president for government affairs at the League of Conservation Voters, said the team of seasoned staff members was chosen specifically to make quick work of reversing Mr. Trump’s policies.
“It was clear that we were coming off of the most anti-environmental, anti-climate action administration we’ve ever had,” Ms. Sittenfeld said. She added: “The need to act immediately was going to be so vitally important. There was a very intentional, very thoughtful, ambitious effort to get highly skilled experts in place right away.”
Reporting was contributed by Lisa Friedman, Noah Weiland, Glenn Thrush, Helene Cooper, Coral Davenport, Katie Benner, and Zolan Kanno-Youngs.