Much of the argument against granting full rights under US and international law to enemy combatants centers on the possibility those prisoners will "return to the battlefield" if released. While that's an acknowledged risk, said Jeremy Shapiro, research director for the Brookings Institution's Center on the United States and Europe, there's more to consider.

"The question of whether a returned detainee poses a danger needs to be weighed against the danger that the existence of Guantanamo is doing every day in creating recruits for terrorism," he said. "It is not simply the case that you will release somebody into a static pool of terrorists. The problem of Guantanamo, the image of Guantanamo, is creating in Europe and the world is, I would argue, on a daily basis adding to our terrorism problem."

Matthew Waxman, now a Columbia Law School professor, served as the Pentagon's chief legal adviser on detainee issues, where he earned the ire of David Addington, the famed enforcer for Vice President Dick Cheney. Waxman's transgression? Insisting that Pentagon guidelines on detainee treatment incorporate language from the Geneva Conventions prohibiting cruel, humiliating and degrading treatment. At Monday's hearing, he advised lawmakers not to seek an easy fix to a complicated problem.

"When I say that there's no simple and ready alternative, what I'm really getting at is there's no easy solution out there that's gonna take care of the whole problem on its own," Waxman told the commission. "[R]ather than looking for a one-size-fits all solution, such as 'send them all to their home countries,' 'bring them all into the United States', 'prosecute them all,' the solution to Guantanamo probably lies in a combination of all of those things."

Then he added another option to the list, one he conceded was "controversial": "new legislation that might create what's sometimes called administrative detention or preventive detention authority—to hold somebody inside the United States."

Rounding out the panel was Gabor Rona, international legal director for Human Rights First, and former legal adviser to the International Committee of the Red Cross, which monitors the treatment of prisoners at Guantanamo. (See Brian Beutler's coverage of how Pentagon advisers and Gitmo officials hoped to evade ICRC detection of cruel and inhumane practices used in prisoner interrogations there.)

Rona took on the very notion of the "enemy combatant" and the standards of what constitutes "hostile acts" against the US.

"The definition of enemy combatant encompasses a huge swath of activities, many of which that have nothing to do with the battlefield—associating with terrorists, for example," Rona explained. "So when the United States releases [an individual] and declares that they are no longer an enemy combatant, that doesn't mean that they had made the correct decision in the first place that this person had engaged in hostilities against the United States." In one case, Rona said, a detainee was deemed to have engaged in hostilities against the US for having published an op-ed critical of "US policies and practices."

Rona also contended that no new legal architecture is needed in the face of the Supreme Court's decision. "If we continue to look for the perfect, we will never find a solution and it will continue to be the enemy of the good," Rona said. "The good is the federal criminal justice system."

—Adele M. Stan, The Media Consortium