The long-term fallout of the war in Iran is only beginning to take shape, but this much is clear: The conflict has left the Middle East unsettled, alliances strained and the world facing uncertain shifts in the balance of economic and military power. Iran’s theocracy is tattered but alive, with new economic leverage. The United States and Israel will hold elections this year, their leaders potentially facing voters having fallen short of their war aims. The NATO alliance, already strained, is under even more pressure. The Gulf Arab states face an emboldened Iran in their backyard. With the U.S. and...