As Colombia prepares to elect a new president, candidates are debating the legacy of Gustavo Petro's efforts to end the country's conflict. A soldier patrols at night in Cucuta, Colombia, an area where rival rebel groups have exchanged attacks [Lucas Molet/Al Jazeera] A soldier patrols at night in Cucuta, Colombia, an area where rival rebel groups have exchanged attacks [Lucas Molet/Al Jazeera] A stillness hung over the muddy waters of the Caguán River, on the fringes of the Colombian Amazon. In the town of Cartagena del Chairá, boats rested against the riverbank, and silence had swallowed the rumble of engines that would ordinarily sputter along the dirt roads. But despite the apparent calm, there was no sense of peace. “People are scared. We are in a very difficult situation. We can’t move for food, supplies or anything. Many children can’t even go to school,” said resident David Rincon, who asked to use a pseudonym.…