DUBAI, United Arab Emirates ? Against the backdrop of a rising sun and an imposing lion, renegade Libyan general Khalifa Hifter strides over rugged terrain in combat fatigues and black boots. The propaganda imagery on Haftar's Facebook page is part of his bid to rally the nation against Islamist militias in Libya's east and their political allies in the capital, Tripoli. It borrows from that employed by Egypt's soldier-turned-president Abdel Fattah El-Sisi, who overthrew an elected Islamist leader before securing power at the ballot box. If Hifter harbors similar ambitions, his will be a far harder task. Successive Libyan governments have failed to unify the forces that removed Moammar...