The problem is that law must translate our ethical standards into rigorously precise language. Sure, we can say that torturing these prisoners was wrong, but how do you write a law that says that lands we lease fall under our own sovereignty? Guantanamo is leased from Cuba. If we pass a law that says that our laws apply to lands that we lease from other countries, then some of them will claim that we are violating their sovereignty.
This is a mess, because there is no law specifying the legal status of Guantanamo. In some cases where we lease lands, we negotiate some sort of deal regarding the applicable law. I don’t know what our lease with Cuba says, but apparently Cuban law doesn’t apply there. Perhaps Guantanamo operates under only American military law — but even American military law forbids torture. I am satisfied, however, that since the question was adjudicated all the way up to the Supreme Court, the Bush Administration was able to find a loophole to exploit.
The sad thing is that this kind of thing is supposed to be addressed by Congress. They should have passed a law specifying that Guantanamo falls under the jurisdiction of American courts. But Congress is barely functional and addresses only the most pressing, immediate issues.