EPA Administrator Lisa Jackson announced on Dec. 27 that she would be stepping down from her position after the president’s State of the Union Address. Robert Perciasepe, who headed EPA's air and water offices during the Clinton Administration, is expected to be a leading candidate to replace Jackson as permanent administrator.

Jackson’s legacy most likely will be her decision that greenhouse gases in the atmosphere threaten the public health and welfare of current and future generations. This finding was prerequisite for the regulation of these gases under the Clean Air Act.

The Administrator’s departure comes as many environmentalists are questioning President Obama’s commitment to dealing with climate change and other environmental issues. After his re-election and a campaign in which global warming was not an issue for either candidate, the President said that his first priority would be jobs and the economy and that he intended only to foster a “conversation” on climate change in the coming months.

In addition to Perciasepe, the list of potential candidates includes California Air Resources Board Chairwoman Mary Nichols and Kathleen McGinty, a former Pennsylvania environment secretary.

Jackson’s replacement likely will have a tumultuous confirmation process. The Senate Environment and Public Works Committee (EPW), chaired by Barbara Boxer (D-Calif.), will hold the confirmation hearing. The nominee unlikely is to fail confirmation because many Democrats on the panel have supported many of the policies EPA adopted under Jackson's tenure. However, several EPA critics sit on the EPW, including Vitter (R-La.), the incoming ranking member.

Republican senators could use the confirmation hearings to reiterate their long-running concerns over EPA's policies developed during Obama's first term. They might also use the confirmation hearing to try and win concessions from the next administrator on key policy goals, a strategy that both Democratic and Republican senators on the Committee have used for previous EPA confirmation processes.