EMANUEL AS COS?…. Rumors about Rahm Emanuel possibly joining the staff of an Obama White House have been circulating for days, and Jake Tapper reports that the offer has already been extended.

ABC News has learned that President-elect Obama has offered the White House chief of staff job to Rep. Rahm Emanuel, D-Ill.

Emanuel, a knowledgeable source tells ABC News, has not yet given his answer. The sharp-tongued, sharp-elbowed, keenly intelligent veteran of the Clinton White House is said to have ambitions to some day be Speaker of the House. But he also has a keen sense of “duty.”

Today on “Good Morning America” ABC’s George Stephanopoulos reported Obama likes the fact that Emanuel “knows policy, knows politics, knows Capitol Hill” and has told associates that Emanuel would “have his back.”

There is a tentative plan to announce Obama’s chief of staff this week.

The speed is not surprising — Obama’s team has take the transition very seriously for several months, and having a White House COS in place this week would be consistent with their general strategy.

As for whether Emanuel would take the job, he’s got a pretty sweet gig right now. It might be tough to lure him from the Hill.

And as for whether Emanuel is a good choice for the Obama White House, I haven’t always been fond of Emanuel the Legislator, but his work in the Clinton White House was impressive, and in many ways, he’s always been more of an executive branch kind of guy anyway. He knows how a White House is supposed to operate, and I suspect, if he accepted the job, Emanuel would serve Obama well.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.