FILE - In this Aug. 4, 2010, file photo, President Barack Obama, joined by adviser Valerie Jarrett and Chief of Staff Rahm Emanuel, right, on the South Lawn of the White House in Washington. Obama is making official what has been clear for days: Rahm Emanuel, the relentless enforcer of his agenda as White House chief of staff, is resigning. (AP Photo/J. Scott Applewhite)

Photo by: J. Scott Applewhite

FILE - In this Aug. 4, 2010, file photo, President Barack Obama, joined by adviser Valerie Jarrett and Chief of Staff Rahm Emanuel, right, on the South Lawn of the White House in Washington. Obama is making official what has been clear for days: Rahm Emanuel, the relentless enforcer of his agenda as White House chief of staff, is resigning. (AP Photo/J. Scott Applewhite)