The problem with all the peace plans for Gaza that U.S., Egyptian, and other foreign diplomats have offered in the past few months is that the parties fighting the war—Israel and Hamas—have very different requirements for stopping it, and therefore they won’t stop it unless and until some allied power forces them to do so. The question is whether those allies have the leverage and the will to make them stop. Seven months into this war, it doesn’t seem that they do. The horrible irony is that neither Israel nor Hamas could keep fighting for long without the material support...