Emanuel has not made a final decision, said the person familiar with Emanuel's thinking, who spoke on condition of anonymity for that reason. The dominant factor at this point is the impact the move and the campaign would have on Emanuel's wife and three young children, who live with him in Washington, the source said.
Should Emanuel leave the White House, President Barack Obama is expected to choose an interim chief of staff. That's likely to be Peter Rouse, one of Obama's senior advisers in the White House and his former chief of staff in the Senate.
Emanuel long has expressed interest in running for Chicago mayor; the incumbent, Richard Daley, isn't running again.
Even Obama acknowledges Emanuel would have to leave soon, should he choose to run, to set up his campaign for the mayoral race in 2011.