Part of the problem is this: If a specific country decides to target specific terrorists, that country may be perceived to be following an agenda that has little to do with the pursuit of justice. Contrary to the belief of a few people on the 'cat, I am not really a blood-thirsty guy. However, I figure terrorists have set themselves 'outside' the justice system, however one defines that. I have read the 'one person's terrorist is another person's freedom fighter' remarks, and they mean nothing to me. If a group has decided that they have the 'right' to kill innocent people just because they have been oppressed, that sets a new set of criteria in motion.
I grew up in a poor family in a poor district. I missed a few meals as a kid, and using terrorist logic, that would give me the 'right' to randomly kill people to drive home the point that capitalism causes poverty (by its Darwinian nature), and because I am oppressed, it's OK to draw the world's attention to my plight in any manner I choose. Bullshit!
Subsequently, I favour a combined special force at the behest of the UN and some sort of world court--Carol C's idea about the court--to hand out the punishment as required. The Hamas leader who got what he deserved at the hands of the Israelis would have got what he deserved at the hands of the UN. However, maybe that would have been more palatable to people and it would have removed a piece of garbage from the world and kept the Israelis out of the flak that followed.