Tony West, the head of the Justice Department's civil division, will become the acting associate attorney general, the No. 3 post at the department.
Associate Attorney General Thomas Perrelli is leaving the post after a busy three-year tenure overseeing some of the department's most sensitive issues, including the ongoing negotiations with companies involved in the Gulf oil spill. Perrelli also was one of the central figures in leading negotiations with five major U.S. banks that resulted in a $25 billion settlement with the nation's top mortgage lenders.
As head of the civil division, West has defended the Obama administration's health care law in the courts and has led the government's lawsuits against state immigration laws passed in Arizona, Alabama, South Carolina and Utah.