Three judges on the federal trial court hearing challenges brought by Guantanamo prisoners are calling on Congress and the Obama administration to enact a law to address one of the nation's most perplexing moral and legal dilemmas: When can the United States indefinitely detain terrorism suspects?

In lengthy interviews, Chief Judge Royce Lamberth and two of his colleagues on the U.S. District Court in Washington, D.C., said that deciding whether to release these prisoners raises unprecedented questions about security and liberty that need to be addressed by lawmakers. Their willingness to discuss their concerns in detail -- something federal judges rarely do in cases pending before them -- underscores the seriousness with which they view the lack of guidance from lawmakers.

"Judges aren't in the business of making law -- we interpret law," said Judge Reggie Walton, a George W. Bush appointee. "It should be Congress that decides a policy such as this that has a monumental impact on our society and makes a monumental impression on the world community."

Lamberth, a Reagan appointee, said the judges are struggling "to adapt legal principles to a whole new sphere of human existence that we've never witnessed in history as far as I know." The problem, he and the other judges say, is that the battle against terrorist groups doesn't fit the classic definition of war, with clearly defined enemies who would be released when the conflict was settled. Because U.S. law doesn't currently have any other option for captives held in a conflict without end, terrorism detainees could be locked up for life, the judges say.

The judges also say the risk in ordering a detainee to be released seems much greater than in past conflicts, because a return to the battlefield is not just a return to traditional frontlines but to possible attacks on civilians.

"How confident can I be that if I make the wrong choice that he won't be the one that blows up the Washington Monument or the Capitol?" Lamberth said.

Neither the Obama administration nor Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., whose support would be crucial to passing such a law, responded to requests for comment on the judges' plea. A Leahy aide indicated that congressional Democrats won't act unless the White House does. "The administration has not yet offered a proposal for a system of prolonged detention," the aide said.

The judges' position drew support from South Carolina Sen. Lindsey Graham, a Republican member of the Judiciary and Armed Services committees who said he'll introduce legislation in the spring to create a legal framework for terrorism detention.

"Our country needs to get a grip on this," said Graham, who for six years was an Air Force lawyer, advising pilots on the law of war during the first Gulf War. "The courts, God bless 'em, are trying to figure out questions that are outside of their lane."

The judges have been working on the Guantanamo cases since 2008, when the Supreme Court ruled that the detainees could contest their detention under the constitutional doctrine of habeas corpus, which protects individuals from unlawful imprisonment by the government. Their task: Determine if the government had enough evidence that a prisoner was involved in al-Qaida or Taliban-linked hostilities to validly detain him as an enemy fighter.

Without any laws or legal precedent to guide them, the judges have had to piece together their own standards for everything from what kinds of conduct constitute enemy activity to how to evaluate evidence obtained from harsh interrogations. Individually they've drawn on general principles of law and one another's work to come up with methods they believe are fair. But the judges say they want central guidelines to answer the many difficult questions these cases can raise, such as how to evaluate the unusual intelligence and interrogation evidence involved and how certain they should be of the truth before delivering a judgment.

"It's an honor to have the responsibility of blazing the trail in determining how justice should be administered in these cases," said Judge Ricardo Urbina, a Clinton appointee. "By the same token it's also at times frustrating when not all the rules are clear and not all the specifics of how a matter should be dealt with are before us."

A major appeals court decision this month gave the lower court some guidance, Judge Lamberth said, but -- as the decision's author herself wrote -- many critical questions about how to evaluate the detentions still demand an answer from Congress.

So far judges have decided 41 of the challenges brought by some 200 detainees and have determined that 32 of the men should be released. Only 21 of those prisoners have actually left Guantanamo, however, because the Obama administration, like its predecessor, is resisting the courts' authority to compel their release -- a dispute that's now before the Supreme Court.

Lamberth said one challenge the judges are struggling with is the prospect of keeping someone in prison for life based on far less evidence than the "beyond a reasonable doubt" proof that is required in ordinary criminal cases. Currently prisoners can be held at Guantanamo based solely on secondhand or even thirdhand reports of their hostile activity, and they don't have the right to challenge the government's informants in court.

"If they meet the definition of enemy combatant, then under our traditional legal authority they're held for the duration of hostilities," Lamberth said. But "how long will the duration of hostilities here last? I don't know, and I don't think anybody on the face of the earth knows. So it makes it difficult for a legal judgment, and I think better suited for a legislative judgment about what other kinds of options might be available."

Graham wants Congress to step in and lift the specter of indefiniteness from the judges' decisions by establishing a process that allows detainees who lose in court to periodically have their cases reviewed.

"Congress should weigh in so that a person is not without a legal remedy forever. That's unacceptable. The detainee should know, the American people should know -- what happens next?" he said.

Graham said legislation should also create clear steps for addressing the greatest fear in these cases: The possibility that someone who is ordered to be released will commit an atrocity.

The judges are duty-bound to set aside such worries because they are allowed to focus only on the facts of the case before them -- the prisoner's activities at the time he was captured, which in these cases was as long as eight years ago.

"I'm sure all of us are concerned about the problem of international terrorism, and all of us were affected one way or the other by the various terrorist acts. But when you have an individual [before you], you can't factor those considerations," Walton said.

The public doesn't always understand the limitations of the judges' role, Urbina said.

He said he was reminded of that not long after he issued one of the most publicized rulings in the Guantanamo cases, deciding that a group of Chinese Muslims, known as Uighurs, should be released into the United States.

He said he was pulled aside at his high school reunion by a "terrifically nice, very successful lawyer."

"What are you doing? These people are terrorists!" Urbina said the lawyer told him. "You want to bring them here, to blow up our cities and our homes and put us all at risk?"

Urbina said he tried to explain that he had looked at the evidence and had done what justice required. "Have you read anything about these people?" he asked the lawyer, "These are people who the government says are not terrorists."

If Congress doesn't pass a comprehensive detention law, Urbina said, the judges will continue answering the detention questions on their own. Armed with almost no precedent and only the Constitution, "we must turn to our common sense, our sense of reasonableness, our overall sense of what the law is created to achieve, and our own kind of visceral understanding of what's fair and what isn't."