Now thatthere are two big questions.
First, what does it mean for the White House?
My guess: not much is going to change. Yes, they are dramatically different personalities. Emanuel is a manic, foul-mouthed, high-profile bundle of energy. About the only thing they have in common is that both are workaholics. Rouse is calm, some say even shy, and prefers to work behind the scenes. There's no reason to believe the Chief of Staff job is going to change that.
But top White House advisors insist -- and I think they're right - that the president runs this White House with a pretty firm hand, and no one staffer is going to change what the president believes or how he operates.
For all his power, after all, Emanuel didn't get his way on two of the biggest issues of the past two years, health care (he wanted a smaller bill) and Afghanistan (he sided with Joe Biden in arguing against the surge.)
Some Democrats lament losing someone with Emanuel's legislative skills, but Rouse too is a formidable legislative strategist. He spent more than 30 years on the Hill, mostly with former Senate majority leader Tom Daschle. Some even called Rouse the 101st Senator, a bow to his ability to get things done.
One area where he could help is dealing with Republicans on the Hill. Rouse was known for reaching across the aisle in the Senate, and if the president hopes to get anything done next year that's going to be a necessity. Emanuel burned some bridges with Republicans over the past two years, and Rouse may be what the White House needs to re-open lines of communication - behind the scenes, of course.
The second big question is whether Rouse (at left) is really taking the job on an "interim" basis.
Officially, the answer is yes. But unofficially, top White House aides are leaving the door wide open to the possibility that Rouse will remain in the job permanently. Rouse has made clear that's not his preference, but if the president gets comfortable with Rouse in the top job the president may well overrule him. Don't forget - Rouse was Senator Obama's Chief of Staff, so it should be an easy transition.
Some Democrats are hoping the president will bring in an outsider to shake things up, to bring in a new set of eyes, to eliminate some of the insularity of this White House. But there's not much evidence the president feels that way.
When Christine Romer departed -- head of the Council of Economic Advisors -- what did the president do? Did he shake up his economic team, as many in both parties demanded? Not even close. He replaced her with Austan Goolsbee, a long-term Obama economic advisor, a man who helped formulate the president's economic policies. Hardly who you'd go to for new ideas.
New blood in the Chief of Staff's office? Don't bet on it.
Rahm and Rouse: "Polar Opposites"
Rahm Emanuel WH Departure to Become Official
Pete Rouse, Insider's Insider, Replacing Emanuel
The Inside Scoop on Rahm Emanuel
Former Bush Chief of Staff on Emanuel's Exit
60 Minutes: Katie Couric Interviews Rahm Emanuel
Chip Reid is CBS News' chief White House correspondent. You can read more of his posts in Hotsheet here.