David A. Welch is University Research Chair and professor of political science at the University of Waterloo’s Balsillie School of International Affairs. Until Saturday, the last time a state unleashed an aerial barrage against Israel was during the Gulf War. In 1991, Iraq, under Saddam Hussein, launched 39 Scud missiles at Israel in the hopes of provoking retaliation that would split the delicate multinational coalition that had amassed to drive his forces out of Kuwait. That coalition included Arab states such as Syria and Saudi Arabia, which he believed would refuse to be seen fighting alongside Israel. Remarkably, that effort...