As I suggested earlier, the ratio isn't completely rigid. If, say, American bombing enrages the younger brothers of many of its victims, turning them into Richard Reids while affecting the total supply of America-hating Muslims less dramatically, then the ratio would change. You can also imagine things that would push the ratio in the other direction. But the ratio is firm enough under enough circumstances that Krauthammer's apparent premise—so long as there will be some angry Muslims, there's no point in reducing the number—is clearly wrong.