For the past four years Tunisian politics have been in near constant disarray, teetering on the brink of a crisis. But an uneasy alliance between President Beji Caid Essebsi, of the secular Nidaa Tounes party, and Rachid Ghannouchi, leader of the Islamist Ennahda party, has kept the fragile government functional. Until now. On Sept. 24, Caid Essebsi confirmed rumors that the four-year alliance between the two men, often called Tunisia's Two Sheikhs, was over. The split between the two political power brokers comes not long before Tunisia's parliament reconvenes in October after a two-month recess, and the consequences of the fracture will make it near impossible for the country to implement many necessary economic reforms....