The Obama administration is moving toward reviving the military commission system for prosecuting Guantánamo detainees, which was a target of critics during the Bush administration, including Mr. Obama himself.
Officials said the first public moves could come as soon as next week, perhaps in filings to military judges at the United States naval base at Guantánamo Bay, Cuba, outlining an administration plan to amend the Bush administration's system to provide more legal protections for terrorism suspects.
Continuing the military commissions in any form would probably prompt sharp criticism from human rights groups as well as some of Mr. Obama's political allies because the troubled system became an emblem of the effort to use Guantánamo to avoid the American legal system.
Officials who work on the Guantánamo issue say administration lawyers have become concerned that they would face significant obstacles to trying some terrorism suspects in federal courts. Judges might make it difficult to prosecute detainees who were subjected to brutal treatment or for prosecutors to use hearsay evidence gathered by intelligence agencies.
Obama administration officials - and Mr. Obama himself - have said in the past that they were not ruling out prosecutions in the military commission system. But senior officials have emphasized that they prefer to prosecute terrorism suspects in existing American courts. When President Obama suspended Guantánamo cases after his inauguration on Jan. 20, many participants said the military commission system appeared dead.
But in recent days a variety of officials involved in the deliberations say that after administration lawyers examined many of the cases, the mood shifted toward using military commissions to prosecute some detainees, perhaps including those charged with coordinating the Sept. 11 attacks.
"The more they look at it," said one official, "the more commissions don't look as bad as they did on Jan. 20."
Several officials insisted on anonymity because the administration has directed that no one publicly discuss the deliberations.
Administration officials said Friday that some detainees would be prosecuted in federal courts and noted that Mr. Obama had always left open the possibility of using military commissions.
Still, during the presidential campaign Mr. Obama criticized the commissions, saying that "by any measure our system of trying detainees has been an enormous failure," and declaring that as president he would "reject the Military Commissions Act."
The military commissions, which were established specifically for trying Guantánamo detainees, have been subject to repeated delays and court challenges that argued that detainees were being denied basic rights of American law. Only two trials have been completed in the nearly eight years since the Bush administration announced that it would use military tribunals.
Any plan to adjust the military commissions would walk a tightrope of granting the suspects more rights yet stopping short of affording them the rights available to defendants in American courts. Several lawyers say the commissions are only beneficial for the government if they make it easier to win a prosecution than it would be in federal court.
The Bush administration's commission system was criticized in part because it permitted evidence that would often be barred in federal court, like evidence obtained through coercive interrogations and hearsay.
The administration is likely to make it more difficult for prosecutors to admit hearsay, while not excluding it entirely, the lawyers said. The hearsay issue is central to many Guantánamo cases because they are based on intelligence reports and detainees may never be permitted to cross-examine the sources of those reports.
Human rights groups said Friday that using any form of military commission would be seen as permitting shortcuts that would not be available in existing American courts.
Anthony D. Romero, the executive director of the American Civil Liberties Union, said that Mr. Obama had pledged to return the country to the rule of law and that "continuing with the military commission system would be a retreat from that promise."
Gabor Rona, the international legal director of Human Rights First, said military commissions would only be necessary if the administration wanted to assure convictions that might not otherwise be certain.
"The administration is making a huge mistake," Mr. Rona said, "if they believe getting convictions through suspect methods is more valuable than letting justice take its course."
It is not clear how many of the remaining 241 detainees are likely to be prosecuted. The four-month suspension of military commission proceedings Mr. Obama ordered is to end May 20. As a result, administration officials are considering whether to ask military judges at Guantánamo for an additional delay. In making such a request, administration lawyers might outline their proposed changes.
In recent days, senior administration officials have hinted publicly that commissions were far from dead, yet offered no specifics and their comments drew little attention. In Congressional testimony on Thursday, Defense Secretary Robert M. Gates said, "The commissions are still very much on the table."
In a news conference this week, Attorney General Eric H. Holder Jr. emphasized that if the administration did use military commissions, the rules must give detainees "a maximum amount of due process."
But, speaking of detainees whom American officials have accused of involvement in major terrorist plots, Mr. Holder added, "It may be difficult for some of those high-value detainees to be tried in a normal federal court."