Yes, some of them have told the FBI that they were there. But at least one says he went only to see what the camp was about–and tried to leave as fast as he could. So how much of a case do prosecutors really have against the six Buffalo-area men arrested for allegedly receiving training at an Al Qaeda camp in Afghanistan?The biggest legal hurdle facing the authorities–who believe that the young men were part of a Qaeda sleeper cell in Lackawanna, N.Y.–is a two-year-old ruling that a critica

Yes, some of them have told the FBI that they were there. But at least one says he went only to see what the camp was about–and tried to leave as fast as he could. So how much of a case do prosecutors really have against the six Buffalo-area men arrested for allegedly receiving training at an Al Qaeda camp in Afghanistan?

The biggest legal hurdle facing the authorities–who believe that the young men were part of a Qaeda sleeper cell in Lackawanna, N.Y.–is a two-year-old ruling that a critical part of the 1996 antiterrorism law under which they have been charged is unconstitutionally vague. That was the view of a federal appeals court in an unrelated California case.

Another likely defense: a freedom-of-association claim echoing those raised by communist defendants back in the 1950s. The issue then was whether people could be prosecuted for being members of–or associating with–the U.S. Communist Party without proof of specific intent to further its illegal goal of violent revolution. The issue now is whether people can be prosecuted for providing "material support" to a foreign terrorist group without proof of specific intent to further its illegal terrorist activities.