The real danger with debt is what happens if lots of people decide, or are forced, to pay it off at the same time.

Paul Robin Krugman (born February 28 1953) is an American economist Professor of Economics and International Affairs at the Woodrow Wilson School of Public and International Affairs at Princeton University Centenary Professor at the London School of Economics and an op-ed columnist for The New York Times. In 2008 Krugman won the Nobel Memorial Prize in Economic Sciences for his contributions to New Trade Theory and New Economic Geography.

According to the prize Committee the prize was given for Krugman's work explaining the patterns of international trade and the geographic concentration of wealth by examining the effects of economies of scale and of consumer preferences for diverse goods and services. His popular commentary has attracted considerable comment both positive and negative.