It's his dream job - as it would be for any Chicago machine disciple who has seen firsthand the enormous power wielded by the mayor in that city. The mayor of Chicago has far more power than a senator or congressman and given that the job also means control of the state's most populous county - Cook County - and the opportunity for further influence and control - the power of Chicago's mayor is rivaled only by the governor in Illinois.

But Rahm has not quite decided to pull the trigger. ABC News:

Although no final decision has been made because of family considerations, ABC News has learned that White House officials are preparing for Chief of Staff Rahm Emanuel to announce on Friday -- as Congress adjourns for recess -- that he is leaving his post to explore a run for mayor of Chicago.

White House officials expect that President Obama will also name an interim chief of staff, perhaps senior adviser Pete Rouse, at the announcement.

Sources close to Emanuel cautioned that he has yet to pull that last trigger on the decision.

Emanuel's likely departure is not a surprise; his mayoral aspirations are well known.

That bit about "family considerations" may be true - up to a point. You might want to include Mayor Daley himself in that "family" because Rahm has almost certainly got several back channels open to the Mayor's office trying to glean Daley's intent.

Hizzoner has made it clear he won't publicly endorse anyone in the Democratic primary. What Emanuel wants to find out is if Daley would oppose him. You better believe Daley is going to have a say in who succeeds him, and the moneymen and politicos who have supported Daley all these years will be quietly given the word on the Mayor's preferences.

Emanuel got his start helping to run Daley's campaigns before running for congress. Does this give him the inside track to succeed him? Ethnic and racial politics in Chicago are very complicated with several factions of black and hispanics vying for turf and goodies. They have had an uneasy alliance with Daley who has especially cultivated the growing hispanic population in the city. It is likely that Daley will look for a candidate that can keep the city united. Rahm may fill that bill but we won't know for a while yet.

Hat Tip: Ed Lasky