And they have been arriving in increasing numbers, providing more than a third of about 530 remaining detainees with representation in federal court. Despite considerable obstacles and expenses, other lawyers are lining up to challenge the government's detention of people the military has called enemy combatants and possible terrorists.
A meeting earlier this month in New York City at the law firm Clifford Chance drew dozens of new volunteer lawyers who attended lectures from other lawyers who have been through the rigorous process of getting the government to allow them access to Guantánamo.
The increase in lawyers for Guantánamo detainees was set in motion last June when the Supreme Court ruled against the Bush administration and said the prisoners there were entitled to challenge their detentions in federal courts.
The rate at which lawyers have stepped forward for the task may be a reflection of the changing public attitudes about Guantánamo Bay and its mission.
"In the beginning, just after 9/11, we couldn't get anybody," said Michael Ratner, president of the Center for Constitutional Rights, a group based in New York that is coordinating the assigning of lawyers to prisoners. The earliest volunteers, Mr. Ratner said, were those who regularly handled death-penalty clients and were accustomed to representing the reviled in near-hopeless cases.
But in recent months, some of the nation's largest and most prominent firms have enlisted in the effort and devoted considerable resources to it, including Wilmer, Cutler, Pickering, Hale & Dorr; Clifford Chance; Covington & Burling; Dorsey & Whitney; and Allen & Overy.
"People are now eager to take this on," Mr. Ratner said. The law firms are bearing all the expenses, he said.
The influx of defense lawyers at Guantánamo Bay also seems to have had some impact on the character of the detention facility. Some of the lawyers say that it was likely a factor in the authorities' decision to end most of the interrogations in recent months. In addition, some lawyers and human rights officials say that the lawyers' presence has reduced reports of abusive treatment by guards and interrogators that previously were the subject of complaints from the Red Cross and the F.B.I.
Maj. Gen. Geoffrey C. Miller, who was the commander of the base for nearly three years, until August 2003, said during his tenure that the system was designed to make the prisoners as compliant as possible in order to make them thoroughly dependent on their interrogators. An important ingredient in accomplishing that, he and other military officials at the base said, was isolation from the outside world.
The arrival of defense lawyers at Guantánamo is an irreversible disruption of that isolation. The lawyers represent the detainees' access not only to federal courts but also to the international news media; the only other authorized visitors, foreign officials and representatives of the Red Cross, do not generally speak publicly about the detainees.
The lawyers' efforts at Guantánamo Bay have not yet resulted in any detainee gaining freedom, but the prisoners' cases are moving slowly through the courts.
In March, James E. Dorsey and John W. Lundquist, partners at the firm of Fredrikson & Byron in Minneapolis, along with Nicole M. Moen, an associate lawyer, traveled to Guantánamo Bay to meet for the first time with their client, an Algerian named Achene Zemiri. After arriving at the base, they were put in drab quarters on the other side of Guantánamo Bay from the main base and prison camp.
The next morning, they traveled by ferry and van to a small prison compound called Camp Echo, which was constructed to handle lawyer-client meetings and is outside the regular prison camp. Each brightly lighted cell is divided in two, with a table and chairs on one side of a heavy metal grate and the inmate's bed and toilet on the other. Mr. Dorsey said that Mr. Zemiri was at first wary and sat with his arms folded tightly around him. But by the end of two days of meetings, Mr. Dorsey said, Mr. Zemiri thanked them warmly and seemed to accept they were there to help him.
He said Mr. Zemiri's wife, who is Canadian, had given them phrases to establish their credibility. "One was the name of a strange soft drink," he said.
Mr. Dorsey, who practices civil law, said he was eager to help "the effort on the part of the bar to see that there are meaningful and just processes." While the firm agreed to the initial representation, partners balked at taking on a second client, who was a reputed Taliban field commander.
Tina Foster, a lawyer at the constitutional rights center who is coordinating the recruitment effort, said that of the 300 lawyers who have signed up, most have not yet been to Guantánamo Bay because the process of getting security clearance is onerous. "Some of the detainees don't even yet know they have attorneys," Ms. Foster said.
The first detainees to get lawyers are those whose families have made an effort. Sometimes, Ms. Foster said, the center learns of a detainee's wish to be represented through letters from other detainees to their lawyers.
Some lawyers have said that interrogators at Guantánamo Bay have tried to discourage prisoners from trusting them. They have said that some inmates have been sharply questioned after their lawyers depart and that others have been told they should not trust lawyers who are Jewish.
One issue the lawyers have had to deal with is advising their clients whether to participate in tribunals being conducted for each detainee to determine whether he is no longer a threat and could be released.
Douglas Cox, a lawyer with Allen & Overy in New York, which represents 14 Yemenis at Guantánamo Bay, said that he had advised his clients to appear before the three-member panels even though they could not be accompanied by their lawyers. "We think that on balance our clients could be helped if they appear," Mr. Cox said.
He said there was an assumption among lawyers that the intent of the new set of tribunals was to release prisoners and reduce population at the base.
Scott Sullivan, a lawyer with Allen & Overy, said that after reviewing the evidence against one of the Yemenis who was arrested in Pakistan, including classified documents, he concluded that "there was nothing to support the case that he was an enemy combatant."