Speaking of just or unjust?
Not all terrorism act is punishable by death. Terrorism is an act to bring out terror from people in general. This kind of act doesn't always have to be a bombing or some kind of weaponry assault like in counter strike games...
Terror phone (only threatening to bomb/to poison something), biker gang terrorism, etc...
Kill the leader... spare the grunts? That is not the perfect solution either. However, in most cases this will stop any terrorizing acts for quite sometime. Terrorists are idealists mostly so someone is bound to step up as a new leader anytime sooner or later.
The interesting part is the labeling of one country as a terrorist country... ALL of them or the majority of them are terrorist? Dude... that is the biggest bull I've ever heard.
So? Kill them all? That will only brings out more hatred to you and more so called "terrorist" sympathizers.
Death is only for the extremists... this kind of terrorists believes that they are god themselves thus are always right... just be careful in differentiating them non extremists... you don't want someone to grow becoming an extreme in the case of vanquishing your existence.
Justice are hard I guess... well... I agree with the death penalty if his/her crime is bad enough. Those that are not killed should be rehabilitated... with family support. Imprisoning them without proper rehab will bound to failure.