Here’s a quote that should be an obvious no-brainer, but it is one most will probably find shocking and astounding: “I would argue that the most serious threat to the United States is not someone hiding in a cave in Pakistan or Afghanistan, but our own fiscal irresponsibility.” So said David Walker, former comptroller general of the United States. And that’s one of the main themes of an incredibly important and timely book just off the presses. It is titled I.O.U.S.A.: One Nation. Under Stress. In Debt. The authors are Addison Wiggin and Kate Incontrera with Dorianne Perrucci. The book...