The race for Sirte is on. Libya's rival militias -- and the two governments that command them -- are competing to win back the city from the Islamic State, which has held it since mid-2015. The victor will secure greater bargaining power in the ongoing high-stakes negotiations to assemble a U.N.-brokered unity government, the Government of National Accord. The negotiations over the new government have attempted to square the disparate interests of federalists, Islamists and secular nationalists, among others, to establish the defeat of their common enemy, the Islamic State, as the priority. This shared goal has enabled the various groups to overlook their severe ideological and tribal divisions -- at least for now....