As Venezuela racks up billions of dollars of arrears with importers that are fueling the worst shortages on record, one of the nation’s top economists is questioning the government’s decision to keep servicing its foreign bonds.

A “massive default on the country’s import chain” is part of what has allowed the nation to keep paying its foreign bonds, Ricardo Hausmann, a former Venezuelan planning minister who is now director of the Center for International Development at Harvard University in Cambridge, Mass., said by phone from Boston. “I find the moral choice odd. Normally governments declare that they have an inability to pay way before this point.”