White House Chief of Staff Rahm Emanuel is reportedly planning to leave his position this week to return to Chicago, where he is expected to run for mayor. Last week, several sources reported that Emanuel would leave before the November elections. His long-discussed departure is no surprise, but the timing is unusual. Though economic advisers Larry Summers and Christina Romers both announced their retirements in recent months, they have little role in the upcoming elections, in which Emanuel would have played a crucial role had he stayed on. So why is he leaving so suddenly?

• Something's Fishy  Talking Points Memo's Josh Marshall writes, "I know people have strong feelings on both sides about Rahm. But I must say I find it somehow unseemly and almost bizarre what a rapid departure he's making. Chief of Staff is usually considered a pinnacle job rather than a stepping stone. You do it until the president is done with you or you burn out, neither of which usually takes very long. And five weeks before an election? On very short notice? It just doesn't seem right."

• Had to Leave Early for Chicago Run  Salon's Steve Kornacki writes, "Ever since Richard M. Daley announced earlier this month that he'd step down as mayor next year after 22 years on the job, the question has been when -- and not if -- Emanuel would make his move. The initial expectation was that Emanuel would stay at the White House through the midterm elections, the customary jumping off point for top aides looking to leave a White House. But the mayoral field is quickly taking shape in Chicago, and in the last few days, pressure had been growing on Emanuel to make his intentions clear. Emanuel apparently got the message."

• Rahm Doesn't Want Responsibility for Bleak Midterms  The Guardian's Michael Tomasky writes of the unusual timing, "Sure: if he wants to run for mayor he'd better get a move on to raise money and so forth. But not even staying until the election? My guess would be that's his timetable, not Obama's. That is, Rahm think the election is going to be a bloodbath, and he doesn't want the articles in the Trib and Sun-Times a few weeks from now to open, 'Former White House chief of staff Rahm Emanuel, fresh off working on an election that was a disaster for his party, announced his candidacy today.'"

• He Needs to Start Campaigning  The Chicago Sun-Times' Lynn Sweet points out, "Emanuel is the only Chicago mayoral contender who has been mute -- totally, not a word on the record --about his thoughts on running for mayor. What we know -- on the record -- has been channeled through third parties who have talked to Emanuel, such as White House senior adviser David Axelrod, Rep. Danny Davis, Rep. Mike Quigley and others." Emanuel is restricted by federal laws that prohibit electioneering from the White House.

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