The face of Congress is about to change, but so is the face of the Obama administration. 

With congressional midterms just two months away, President Obama has already seen top-level advisers head for the door and more turnover could be on the way before the end of the year. 

Such a shake-up would be in line with the cycle of past administrations -- the midterms typically set the stage for presidents to re-shape their inner circles. The most drastic example came from Jimmy Carter, who cleared house across his Cabinet and staff in 1979. 

No president has followed in Carter's footsteps, but the Obama White House acknowledges change is coming, in some degree. After two years marked by bloody battles over health care, financial regulation and war, fatigue has set in and the president may be looking for a fresh start. 

"There's no doubt that there will be people that return to their lives and their families," White House Press Secretary Robert Gibbs told reporters this week. 

The White House announced one change of the guard Friday when Obama installed economist Austan Goolsbee to the head of the Council of Economic Advisers, after Christina Romer left to return to the University of California at Berkeley. Budget director Peter Orszag also left the administration over the summer. 

Who's next is anybody's guess, but speculation this week centered on White House Chief of Staff Rahm Emanuel, who seemed to get his political wish when Chicago Mayor Richard Daley announced he would not seek reelection. 

Emanuel has described Chicago mayor as his dream job and his colleagues at the White House say he will be taking time to decide whether to run for the office. He's by no means a shoo-in for the job, but with the filing deadline set just weeks after the November midterms, Emanuel would have to make his decision soon. 

An Emanuel exit would mark a major shift in the tone and likely direction of the Obama White House -- but Democratic strategist Joe Trippi said it might be coming at the perfect time. If Republicans gain enough seats in Congress to turn at least one chamber red, Emanuel's hard-charging style might not fit the bill anymore. 

"Rahm may have been the wrong guy to be chief of staff in that environment," Trippi said. "You're going to have a different environment from when Rahm was made chief of staff." 

Trippi speculated that senior adviser David Axelrod might be next to flee Washington. The Washington Post reported this week that Axelrod is expected to leave after the elections, though he could transition to launching Obama's 2012 reelection campaign. 

Trippi said the most likely candidates for departure are those who have been with the president since the start of the campaign -- effectively serving a full four years, through a grueling presidential election followed by grueling policy battles on the Hill. 

"It's very tough not to get into just massive fatigue," Trippi said. 

Gibbs made that point when asked about possible departures Wednesday. 

"I will say, too, for those that were on the campaign, this is sort of the end of year four, not necessarily the end of year two," Gibbs said. 

Though Gibbs' plans are unclear, press secretaries have some of the shortest shelf lives in Washington. Ari Fleischer left as President George W. Bush's top spokesman in mid-2003; Dee Dee Myers left that job under President Clinton shortly after the midterms in 1994. Clinton's chief of staff, Mack McLarty, also left the summer before the midterms, replaced by Leon Panetta, now CIA director. 

The scope of the Obama staff changes could depend on the severity of his party's losses in November. But any turnover in the Obama team, where loyalty borders on faith, raises questions about the president's ability to hold his agenda together in the face of a potentially divided Congress. 

"There are few people who ever are going to have the trust ... as much as Rahm and Ax," Trippi said.