Venezuela and Guyana are a study in contrasts. The former was once an oil-exporting heavyweight with a thriving economy to match, before its energy sector was brought low during two decades-plus of mismanagement and corruption under Maduro and his predecessor, President Hugo Chavez. Meanwhile, within the space of several years, Guyana — a much smaller nation, initially far poorer but also more politically stable — developed the world’s fastest-growing economy as Exxon and other international operators flocked to its offshore oil reserves.