Pete Rouse (official White House photo)

MSNBC is reporting that the White House is confirming what pretty much all Washington watchers have known for a fortnight: Rahm Emanuel will resign his postion as President Obama’s Chief of Staff to run for mayor of Chicago.

Pete Rouse, currently a senior advisor to the president, will be named the new Chief of Staff on an acting basis. Rouse was Obama’s CoS when the president was Illinois senator;  he previously held the same job for South Dakota Sen. Tom Daschle.

Update: The New York Times Caucus blog reports Rouse will not be just an “acting” CoS:

Mr. Rouse will not be named interim chief of staff, but rather will formally take over Mr. Emanuel’s title. While Mr. Rouse has expressed reservations about holding the chief of staff job for an extended period, he has agreed to do the job – for now.

Mr. Rouse has a low profile outside the White House and across Washington, but he is extraordinarily close to the president and is respected inside the West Wing and on Capitol Hill, where he was known as the “101st Senator” during his role as an adviser to Senator Tom Daschle of South Dakota, then the Democratic leader.

Update: Robert Gibbs is currently announcing that the president will have a “personnel announcement” tomorrow at 11:05 AM eastern time.