It wasn’t that long ago that Venezuela, which possesses the world’s largest crude oil reserves, was a relatively stable democracy with one of Latin America’s fastest-rising economies. It was a nation so awash in petroleum revenues that the socialist government of the late former President Hugo Chavez spent huge amounts on social programs and, at one point, even provided free heating oil for impoverished Americans. But starting in 2014, the South American nation began suffering a startling collapse. With Venezuela’s gross domestic product plummeting even more than the United States during the Great Depression, many of its nearly 32 million...