WASHINGTON -- President-elect Obama plans to use his executive powers to make an immediate impact when he takes office, perhaps reversing Bush administration policies on stem cell research and domestic drilling for oil and natural gas.

John Podesta, Obama's transition chief, said Sunday Obama is reviewing President Bush's executive orders on those issues and others as he works to undo policies enacted during eight years of Republican rule. He said the president can use such orders to move quickly on his own.

"There's a lot that the president can do using his executive authority without waiting for congressional action, and I think we'll see the president do that," Podesta said. "I think that he feels like he has a real mandate for change. We need to get off the course that the Bush administration has set."

Podesta also said Obama is working to build a diverse Cabinet. That includes reaching out to Republicans and independents _ part of the broad coalition that supported Obama during the race against Republican John McCain. Defense Secretary Robert Gates has been mentioned as a possible holdover.

"He's not even a Republican," Senate Majority Leader Harry Reid of Nevada said. "Why wouldn't we want to keep him? He's never been a registered Republican."

Obama was elected on a promise of change, but the nature of the job makes it difficult for presidents to do much that has an immediate impact on the lives of average people. Congress plans to take up a second economic aid plan before year's end _ an effort Obama supports. But it could be months or longer before taxpayers see the effect.

Obama could use his executive powers to at least signal that Washington is changing.

"Obama's advantage of course is he'll have the House and the Senate working with him, and that makes it easier," said Carl Tobias, a law professor at the University of Richmond. "But even then, having an immediate impact is very difficult to do because the machinery of government doesn't move that quickly."

Presidents long have used executive orders to impose policy and set priorities. One of Bush's first acts was to reinstate full abortion restrictions on U.S. overseas aid. The restrictions were first ordered by President Reagan and the first President Bush followed suit. President Clinton lifted them soon after he occupied the Oval Office and it wouldn't be surprising if Obama did the same.

Executive orders "have the power of law and they can cover just about anything," Tobias said in a telephone interview.

Bush used his executive power to limit federal spending on embryonic stem cell research, a position championed by opponents of abortion rights who argue that destroying embryos is akin to killing a fetus. Obama has supported the research in an effort to find cures for diseases such as Alzheimer's. Many moderate Republicans also support the research, giving it the stamp of bipartisanship.

On drilling, the federal Bureau of Land Management is opening about 360,000 acres of public land in Utah to oil and gas drilling. Bush administration officials argue that the drilling will not harm sensitive areas; environmentalists oppose it.

"They want to have oil and gas drilling in some of the most sensitive, fragile lands in Utah," Podesta said. "I think that's a mistake."

Two top House Republicans said there is a willingness to try to work with Obama to get things done. But they said to expect Republicans to serve as a check against the power held by Obama and Democratic leaders in Congress.

"It's going to be a cheerful opposition," said Rep. Mike Pence, R-Ind. "We're going to carry those timeless principles of limited government, a strong defense, traditional values, to the American people."

Pence, of Indiana, is expected to take over the No. 3 leadership post among House Republicans.

In other transition matters, Obama's new chief of staff, Rahm Emanuel, would not say whether Obama would return to the Senate for votes during the postelection session this month. Obama's presence would be extraordinary, given his position as president-elect, especially if Congress takes up a much-anticipated economic stimulus plan.

"I think that the basic approach has been he's going to be here in Chicago, setting up his economic, not only his economic team, but the policies he wants to outline for the country as soon as he gets sworn in, so we hit the ground running," Emanuel said.

Also, Emanuel would not commit to a Democratic proposal to help the auto industry with some of the $700 billion approved by Congress to for the financial bailout.

Reid and House Speaker Nancy Pelosi, D-Calif., said in a letter Saturday to Treasury Secretary Henry Paulson that the administration should consider expanding the bailout to include car companies.

Podesta appeared on "Fox News Sunday," as did Pence, and CNN's "Late Edition," where Reid also was interviewed. Emanuel spoke on ABC's "This Week" and CBS' "Face the Nation."