After more than a year of talks, U.N.-backed political negotiations in Libya yielded a deal Dec. 18 to forge a unity government. The landmark agreement seeks to end the long-running rivalry between the internationally recognized government in the eastern city of Tobruk, the House of Representatives, and the General National Congress based in Tripoli. The United Nations tried to include wide regional and tribal representation in Libya's unity government to represent the country's diverse array of interests. However, the agreement will be difficult to implement....