This is clear when you look at all the different cases and trials brought from 2001 through 2009.
The exception was Jose Padilla. But in that case, if you take the claims at face value, the key was that we knew he wanted to carry out attacks but we didn't have evidence of any actual crime. Again, you can dispute just what we knew and whether detention as an enemy combatant is constitutional. But the key point is, as I said, it didn't even occur to someone that we wouldn't just put on trial someone who was literally caught in the act of trying to blow up a plane and then -- if the reports are accurate -- proceeded to confess and provide all sorts of details of his plot to authorities once he was taken into custody.
The argument for trying Umar Farouk AbdulMutallab in a military court is one that comes that comes from the campaign committees of the Republican party. There's just no two ways about it.