How Debt Sinks A Superpower

Tyler Cowen worries:

At some sufficiently high debt-GDP ratio, it becomes a foreign policyissue and a big one.  Postwar UK had a high debt to GDP ratio, and tothis day it is a fine place, but that debt meant the end of England asa world power, for better or worse.  The U.S. for instance usedfinancial issues to push England around and they basically had to giveup on their overseas commitments.  A very high debt ratio here wouldmean the end of the U.S. as a global world power, again even if GDP...