Tens of thousands of angry Venezuelan voters marched through central Caracas yesterday, defiantly pumping the tropical air with their fists. They chanted the decades-old mantra of  Latin America’s left: “El pueblo unido jamás será vencido.” In the upside-down  of  today’s Venezuela today, this roar of “The people, united, will never be defeated” was a demand to end a quarter century of  socialism and the resignation of its leader, President Nicolás Maduro.