JERUSALEM — Until recently, many believed that the promise of progress in the 21st century would enable us to move beyond the barbaric horrors of the past toward a brilliant future — that we could go about our comfortable lives and that evil would simply pass us. It will not. The horrors that Hamas perpetrated Oct. 7 remind us that we won’t realize the promise of a better future unless we, the civilized world, are willing to fight the barbarians. The barbarians are willing to fight us, and their goal is clear: Shatter that promising future, destroy all that we...