The topic was proposed by a student in the class who had actually thought about it beforehand, no one else had any good ideas.
The "winner" of the debate was determined by a panel of other teachers (part of the reason he got in trouble the teachers were "ruling" on gov't policy). Nobody seems to understand that the people (me and a few others) defending the US's policys could actually win. Everyone assumed that it was biased by his politics such that obviously the result would be anti-American. It was actually quite fun. Though I'd say that the reason my group won was largely becuase in 2006 a lot less was known about Gitmo. We could do a lot of "you can't prove that X Y or Z is happening, that is just conjecture", that we wouldn't be able to do today.
As a side note, I'm firmly in the anti-toture and anti-DU camp, but I always find it more interesting in debate to side with the group you disagree with.