Obama and others have said the US has never defaulted. In fact, though, at least a small instance of technical default has occurred, economists say. In the spring of 1979, some investors in short-term Treasury bills faced delayed payments. The Treasury blamed the glitch partly on Congress’s failure to act in a timely way on the debt ceiling, and partly on problems with its computer equipment.
Some economic research concludes that even this small instance of default had a lasting negative effect, pushing up federal borrowing costs. In recent testimony on Capitol Hill, Mark Zandi of Moody’s Analytics said the incident “has cost us tens of billions of dollars.”
