Imagine that, one way or another, a powerful group of terrorists took over a part of Canada and started lobbing missiles into US border towns. And, imagine, that this group was happy to round up Canadian civilians to stand, at gun point, next to the missile launchers.
Would anyone suggest that the Americans were not entitled to hit the launchers?
Certainly if some kind of terrorist organization were to set up missile factories across the frontier in Canada and Mexico and start attacking targets in the United States, the American people would demand that their President use all necessary force without stint or limit until the resistance had been completely, utterly and pitilessly crushed. Those Americans who share this view of war might feel sorrow at the loss of innocent life, of the children and non-combatants killed when overwhelming American power was used to take the terrorists out, but they would feel no moral guilt. The guilt would be on the shoulders of those who started the whole thing by launching the missiles. walter russell mead