A polarized Egypt will likely remain enveloped in violence because the Muslim Brotherhood lacks incentive to rejoin the political process, a regional expert said Monday. Almost 300 people have died since Gen. Abdel Fattah al-Sisi deposed President Mohamed Morsi, the Muslim Brotherhood leader, on July 3. Morsi’s authoritarian rule prompted secular Egyptians and others to back the military’s actions, but supporters of the Islamist Muslim Brotherhood argue that the country’s first democratically elected leader should be reinstated. The Muslim Brotherhood has refused to “swallow the reality” of Morsi’s exit, despite pleas from international diplomats and an offer by the military...