Just A WOT Question

I believe that people who make threats should be taken seriously. I think our law enforcement ought to treat terroristic threats more seriously than we do. I think when a person publically announces that he will help people attack the United States, he should be considered an enemy of our country. These seem like reasonable positions to me. Last I heard, we either capture and hold, or kill, our enemy.

So, when we run into the father of a known suicide terrorist, and he is saying stuff like this, why don't we just have some mid-level operative in his home country come by one night and kill him?

Could it hurt our cause? I doubt it. Could he be hurting our cause if left alive? Well, I think he should be taken at his word on that point.

I'm not saying we should just walk up and kill him. I'm just asking. Why don't these people "disappear"? And the fact that they don't just "disappear" -- doesn't that say something tremendous about our country and its rules of engagement?