Updated

If history is any guide, then Republicans can expect to gain House seats in next year's mid-term elections.

In the past century, only two presidents have avoided losses in the House for their political party in their first mid-term elections: George W. Bush, in the aftermath of the Sept. 11 terrorist attacks, and Franklin D. Roosevelt in 1934 during the Great Depression.

"But those are the two exceptions that prove the rule," said Larry Sabato, director of the University of Virginia Center for Politics. "In the other cases since World War II, about 17 House seats have been lost on the average in the first mid-term election for the president's party."

No one expects Republicans to win the 40 seats they'd need to take back the House but they're likely to start chipping away. That's not comforting to those working to re-elect Democrats in 2010, such as Rep. Chris Van Hollen, chairman of the Democratic Congressional Campaign Committee, but neither is it a surprise.

"Way back in January, we made it clear to our members on the Democratic side, get ready, fasten your seat belts because this is going to be a tough cycle," the Maryland Democrat said. "And the good news for us is, they've been preparing from day one."

The first round of congressional elections for a new president is always a challenge. For one thing, the soaring rhetoric about coming together, for which Obama was famous, is far more unifying that actual governing, in which any policy decision is bound to please some but disappoint, even irritate others.

"So you have liberals now (in the House) and some of them (are) complaining that the Obama administration isn't doing enough in the direction they'd like to see," political analyst Michael Barone told Fox News.

Not enough, for instance, to push a full bore government-run insurance plan, or to wind down the wars in Iraq and Afghanistan, among other things.

While such policy decisions can sap the enthusiasm of supporters, they can also energize opponents.

"There's a lot of enthusiasm among opponents of some of the president's programs and the Democratic proposals," Barone said, "and much less enthusiasm among the Democrats and the Obama fans than there was a year ago."

While Democrats have a comfortable margin in the House, that is not the case in the Senate where Democrats have just enough votes to prevail.

"If the Republicans are able to bring the Democrats down from their current 60 to even 57 or 58, they will be able to win a lot of votes on the floor of the Senate since of course you need 60 to cut off debate," Sabato said.

With slimmer margins in both chambers of Congress, the most ambitious parts of the president's agenda could be at risk. The mid-term elections can determine how much support and running room a president has or whether his power starts to wane halfway through his term in office.

Fox News' Jim Angle contributed to this report.