Lisa Jackson
Highs: Emerging as perhaps the most influential administrator in the EPA's 40 year history, Jackson pushed for tougher regulations in a number of environmental areas, from air pollution to water pollution, as the Obama Administration began to undo the deregulation that marked the Bush White House. With the failure of cap and trade legislation to pass Congress, regulations from her office will be the only way the White House will be able to curb carbon emissions.
Lows: The EPA came under criticism for not doing enough in response to the Gulf oil spill-which hit hard for Jackson, a New Orleans native. With the Republican midterm victories in November, life is about to get much tougher for the EPA head-G.O.P. House leaders have said they'll call Jackson to testify on environmental regulations they view as executive overreach.
—Bryan Walsh