@Independent

The way I see this is that the problem with executing the 9/11 terrorists is that you risk making them Martys, If goes wrong and they survive, they will claim it cements a narrative that Allah has protected them from the evil infidels.

In Lord of the rings, I think it is Éowyn says she does not fear death, she fears a cage and to be locled up until old agve removes all chance of glory. So perhaps keeping these people locked up is the more logical thing to do.

If you execute, then their place of burial will become a shrine and a calling card to rise up further against the west.