US Attorney General Eric Holder took office pledging a sharp shift away from the last administration's policies, but an apparent change of heart in the White House could see the top lawyer leave his job.

Holder, 59, is the first African-American to hold the top legal post, and was generally regarded with bipartisan respect when he took office.

But a series of gaffes, fights with both Republicans and Democrats, and apparent disagreements between him and the White House have left Holder looking increasingly embattled.

He came under renewed fire when he told lawmakers Tuesday that Osama bin Laden would not be captured alive, and that US officials would read legal rights to the Al-Qaeda leader's corpse.

But the ridicule and attacks that followed are only the latest blows Holder has faced in the 14 months since he took office pledging to reverse the worst "war on terror" legal abuses sanctioned by former president George W. Bush's administration.

Ultra-conservative activists have questioned his ethics and even his patriotism over his decision to hire lawyers who defended terror suspects to Justice Department posts.

He has also raised the ire of Republicans by seeking to investigate CIA practices during the "war on terror," even over White House opposition.

This week, Republicans also reproached him for having failed to inform them during his nomination hearings that he had supported a lawsuit challenging Bush-era legal policies on detention.

But the attorney general also faces political attacks from the opposite end of the political spectrum, with left-leaning lawmakers and activists angered by his decision not to penalize Bush administration lawyers for justifying the use of harsh interrogations techniques.

They are also outraged that the Justice Department has agreed to continue prosecuting some terror suspects before the military tribunals set up by Bush's administration.

But the final straw for Holder may be the increasing distance between him and Obama on national security issues.

The White House has relented on its original insistence to prosecute five men accused of plotting the September 11, 2001 attacks before a civilian court in New York City.

Strongly defended by Holder, the plan was intended in part as a symbolic gesture to showcase how differently Obama dealt with the prickly subject than his predecessor.

Holder has refused to back away from the plan even as reports suggest the White House will agree to prosecute the five men before a military court in return for Republican support for the closure of the Guantanamo Bay prison camp.

"I think if the president overrules him on what should be done with the detainees, I think he should resign," Yale Law School professor Eugene Fidell told AFP.

"I think a disagreement on a matter as profound as this is the type of thing that people can conscientiously resign about.

"If you consider that you're not getting anywhere and that the matter is important enough, then you leave," he added.

According to Michael Gerson, a former Bush adviser, Holder is now "the most endangered member of the Obama cabinet."

"Just about everything he has touched has backfired," Gerson wrote in The Washington Post, adding that the White House has shown little inclination to defend Holder against his latest critics.

Holder's spokesman Matthew Miller declined to comment.

The attorney general's dilemma is similar to that of Greg Craig, Obama's former White House counsel, said John Bellinger, a conservative former legal advisor to then-secretary of state Condoleezza Rice.

Craig was a leading proponent of the administration's pledge to close the controversial Guantanamo facility within a year, but resigned in November as it became clear the deadline would be missed.

"What happened in both cases is that while the administration made the right decision, they did not do enough to lay the groundwork to get political support for the decisions that they have made," Bellinger said.

Holder's future plans remain unclear, but the resignation of such a high-profile cabinet member could put Obama himself in an awkward position.

"We do not have much of a tradition of resignation on principles in our political system," said Fidell. "It doesn't happen."