Last week, Secretary of State Antony J. Blinken headed for the Middle East to try to keep Israel’s war in Gaza from spinning out of control, and to begin talks on what diplomats call “the day after” — what happens after the shooting stops. Who will govern a shattered Gaza? Who will feed and house its refugees? Who will police its ravaged streets? And perhaps improbably, can the war, however brutal its toll, be turned into an opening for a wider peace? “When this crisis is over, there has to be a vision of what comes next,” President Biden said...