They didn't. And it was explained over and over in even the liberal news media by Ashcroft and others WHY he was tried as he was. Did you miss it? How is it people who are disappointed, or disgusted, or whatever, with the "Bush Administration" have conveniently missed out on previous info?
I believe they are using Lindh for nothing more than intelligence. In return, he only gets 20 years. Now, correct me if I'm wrong, but if he decides to not cooperate, all deals are off the table and his sentense will be changed.
Sure, I'd like to see the bastard hang, but if he can provide any intelligence that we couldn't get otherwise, then letting him rot in a prison- at the mercy of the scum of society, is fine by me.