I think a properly written declaration might have simplified things with this case.
Probably part of the problem is that some of what Al Arian did was legal at the time he did it. Proving the connection between him and the people he supported is easy; proving the connection between him and the actions they took gets more difficult.
But if you declare yourself at war with a given group, it ought to be much easier to simply demonstrate that he is on their side and either take him into custody on that basis alone, or revoke his citizenship on that basis alone.
Lincoln has been criticized for revoking Habeus Corpus during the Civil War, and threatening to jail judges. Whatever the particulars of the individual cases, he at least understood that he was at war, and he was prepared to do what he had to do. When you are at war, you are in what in many countries is called a "state of emergency". If people declare their support for the enemy, you round them up. You can always apologize later after the war is won.
Man, I like that policy. However in the current circumstances, it would require a new "Democrat Wing" at Gitmo!!
Specificaly, on Sami al-Arian. I read that much of the governments case was weakened by the requirement to protect undercover sources and methods.
Got any info on that angle?