By narrowly rejecting an agreement between the government of Colombia and the nation’s largest guerrilla group, Colombian voters have thrown a four-year-long peace process into turmoil. There may still be a chance of renegotiating the terms of the deal to end the brutal 52-year insurgency, but the political hurdles are high and the window of opportunity is narrow. Hope now largely rests in the exhaustion of both sides. Neither the government nor the rebels —…