He has criticized Bush's attempts to trump Congress, especially on war issues.
Washington - As a US senator and presidential candidate, Barack Obama routinely criticized the accretion of presidential power during the Bush years.
But in the run-up to assuming the presidency himself, the president-elect has gone silent on whether he would roll back powers claimed during the Bush years - or support congressional efforts to do so.
The president does not have the constitutional right to trump laws of Congress when he deems it necessary, he said on the campaign trail.
When asked, then-Senator Obama said that he would not use signing statements to subvert the intent of congressional laws - a device used by President Bush to challenge hundreds of points of law. Nor would he challenge congressional limits on the deployment of US forces abroad.
"As president, I will not assert a constitutional authority to deploy troops in a manner contrary to an express limit imposed by Congress and adopted into law," he said in a Dec. 20, 2007 interview with The Boston Globe, circulated by the transition team.
As a US senator, he introduced a resolution (S.J. Res. 23) that stated that "any offensive military action taken by the United States against Iran must be explicitly authorized by Congress."
But some civil libertarians say that the precedents of the Bush years are so threatening to a constitutional balance of powers that Obama should act swiftly in the new administration to restore that balance.
"The countless abusive policies of the past eight years and the extreme legal theories on which they were based have left our nation weaker and our constitutional framework in a precarious position," said Sen. Russ Feingold (D) of Wisconsin in a Dec. 10 letter to the president-elect.
"In light of this recent history, I believe that one of the most important things that you can do as president is to take concrete steps to restore the rule of law in this country," he added. "I am sure that as a constitutional scholar you can appreciate that we must ensure that the Bush administration's views of executive supremacy do not become so ingrained in our system of government that they become the 'new normal'."
Some of these issues will need to be resolved by the courts and the Congress. But civil libertarians in and out of the Congress say that the Obama administration could signal a change of course by making restoring the rule of law a key point in his Inauguration Address.
The new administration could also draft executive orders reversing Bush era policies and procedures on issues ranging from separation of powers and excessive government secrecy to domestic surveillance and the treatment of detainees.
With his choice of Eric Holder - a deputy attorney general in the Clinton administration and an outspoken critic of Bush-era claims of executive power - as nominee for attorney general, Obama has sent early signals that he's serious about abuse of power issues.
"With his promise to close Guantánamo and the Holder nomination, he has made the right noises rhetorically that may be difficult to back away from," says Gene Healy, a vice president at the Cato Institute, a libertarian think tank in Washington.
"But I think it's really unlikely that even with the best of intentions that Barack Obama is going to meaningfully deimperalize the presidency," he adds.
Conventional wisdom holds that no branch of government gives up powers once acquired.
"It's one thing to campaign against excessive executive power and it's another to give it away once you have it," says Julian Zelizer, a congressional historian at Princeton University in Princeton, N.J.
"It's still questionable whether he will make the effort to undo what President Bush has done, especially when Democrats control both houses of Congress," he adds.
So far, Democratic leaders aren't tipping their hand on how quickly - or if at all - they will push back on executive claims of power.
But Senate majority leader Harry Reid has signaled that the vice president will not be invited to attend weekly Democratic caucus lunches. It's a sign that as vice president, former Sen. Joseph Biden won't have the clout with the Democratic caucus that Vice President Cheney wielded with Republicans.
"There may be times when administration officials may be invited to attend, but these are member-only lunches," said Jim Manley, a spokesman for the majority leader.
Some civil libertarian groups say they are cautiously optimistic that the Obama campaign rhetoric will produce changes in how the White House asserts executive power.
"Obama is a constitutional scholar. He's also the first senator to be elected since [Lyndon] Johnson. That might give him a somewhat different attitude on how he interacts with the legislative branch," says Caroline Fredrickson, director of the Washington Office of the American Civil Liberties Union.
"We're going to make a big push for Congress to put some boundaries on where the state secrets doctrine can be asserted," she adds. Sen. Edward Kennedy (D) of Massachusetts is ramping up legislation on this issue.
"The problem is that when a president gets this power, his highly trained and highly priced lawyers around him are going to be urging him to preserve that power," said Senator Feingold.