A little more than a year after a peace deal between the Colombian government and the Revolutionary Armed Forces of Colombia, or FARC, was struck, the rebels have officially surrendered their weapons to U.N. mediators, bringing the country's largest and longest-running insurgency a step closer to ending. But perhaps the most crucial challenge for the successful implementation of the peace agreement hammered out over a four-year span lies ahead. In exchange for the rebels' laying down their arms, FARC negotiators insisted that their leaders who face criminal convictions receive amnesty and that the group be integrated into the country's political process. To enact those concessions, several pieces of legislation must be approved by the Colombian Congress, where the margin of error for the ruling party is razor-thin....