ARNOLD KLING: Guessing the Trigger Point for a U.S. Debt Crisis. “Leading authorities in the United States, including the Congressional Budget Office, use the term unsustainable to describe the long-term fiscal outlook. . . . This paper explores the possibility of the U.S. experiencing a debt crisis in the medium run, meaning somewhere between 2015 and 2035. It is impossible to state precisely the trigger point for a crisis. At best, we can make guesses about some of the key parameters.”