When it comes to governments which support terrorism, "decapitate and wait."
For countries which harbor terrorists, but we cannot be sure they do so knowingly, demand cooperative investigations. If the cooperation we insist upon is refused, we decapitate and wait. If the cooperation is offered, the investigations will, in time, provide the answers, and also in time, take a major step toward corraling the terrorists operating there.
I think that those who disagree with the necessity of American imperialism do so because they are rightly appalled by the prospect, and because everyone has been conditioned to think that imperialism is wrong, unworkable, etc. The fact is that imperialism has worked every time it was properly tried; every time an imperial nation retreated from its obligations overseas it did so because it wanted to, not because it had to, in a bout of imperial laziness, and every time it retreated, it bought itself more trouble and closer to home.