Let's start with the clear cases. Assume these facts: a detainee is captured in Afghanistan, wearing the uniform of the Taliban (if such exists), expressly states he is a member of the Taliban and specifically invokes the protections of the Geneva Conventions for prisoners of war.
I hope this is a noncontroversial case - a person captured in a theater of war who expressly claims to be a combatant entitled to the protections afforded by Geneva. Does it become "outrageous" preventive detention if the detainee is held in the United States? If so, why?
As you can see, I think the concept of "preventive detention" is not the issue here, but the scope of its application. That is what is to be determined by the process to be implemented - particularly the processes for review of Executive Branch determinations.
What showing must the Executive Branch make in order to support a decision to declare a detainee an "enemy combatant?" What is the burden of proof? What is the process of review? What type of evidence will be admissible?
I've discussed one hypothetical that seems clear cut to me. Let me provide one the seems clear cut in the other direction: a detainee is a US citizen, captured in Chicago, denies any ties to groups hostile to the United States, both state and non-state actors, and there is no physical evidence that adds to the Executive Branch's assertion. The only evidence that government has is an intelligence report gleaned from an interview taken in another country and the witness cited in the report is no longer available for questioning. The witness is reported to have said that he was told that the detainee was working with a terrorist group.
Easy case. The Executive Branch does not even come close to making its case. Unconfronted, unconfirmed double hearsay testimony does not cut it. The review process should result in release of the detainee because the Executive Branch's designation of the detainee as an "enemy combatant" is not close to being proven.
Now those are the easy cases - PROVIDED a proper process is in place. The harder cases obviously fall in between these two examples.
The discussion on preventive detention should be about how we handle the cases in between.
Speaking for me only