The plunge in the price of oil is causing more investors to bet that Venezuela will default on its $120 billion pile of foreign debt, an event that would trigger a messy battle over the country's oil shipments and deepen its economic and political crisis. Despite Venezuela's worst economic slump since independence from Spain, the socialist government has continued to pay bondholders on time. President Nicolás Maduro this week reiterated the country's intention to honor its debt. Few investors doubt Venezuela's willingness to pay. In recent years, it has paid bondholders partly by drastically reducing the amount of dollars it...