After mass protests and international pressure failed to unseat President Nicolás Maduro of Venezuela, it became clear that it would take defections from within his own government to remove him from power. Now, secret documents suggest that some of Mr. Maduro’s people are starting to turn on him. Guest: Nicholas Casey, the Andes bureau chief for The New York Times. For more information on today’s episode, visit nytimes.com/thedaily. Background reading: A secret dossier compiled by Venezuela’s intelligence agency and provided to The New York Times shows how Tareck El Aissami, a confidant of Mr. Maduro, became a wealthy man even as his country headed toward economic collapse. Listen to a series from “The Daily” about Leopoldo López, a prominent opposition politician who was put under house arrest after staging protests in 2014.