Departing U.S. Environmental Protection Agency head Lisa Jackson did well by the public, especially with the tighter emissions rules she imposed on coal-fired power plants.
But her successor will need to move Congress closer to meaningful legislation on climate change and rebuild the program that funds much of the nation's sewerage work.
Ms. Jackson, the first African American to lead the EPA, helped secure landmark fuel-efficiency standards for autos. She infused new life in the agency after eight years of foot-dragging and rollbacks by former President George W. Bush's administration.
Although the Obama administration backed off its push for climate legislation after the 2010 election, Ms. Jackson directed EPA initiatives that are reducing the most prevalent greenhouse gas, carbon dioxide, as well as one of the worst neurotoxins, mercury.
Ms. Jackson could have been even more effective if Mr. Obama had allowed her proposed new standard for smog-forming ozone to stand in 2011.
Expecting a conservative backlash, the president withdrew the standard until after the election. He now needs to name a successor who will pick up where Ms. Jackson left off.