When national debts have once been accumulated to a certain degree, there is scarce, I believe, a single instance of their having been fairly and completely paid. The liberation of the public revenue, if it has ever been brought about at all, has always been brought about by bankruptcy; sometimes by an avowed one, but always by a real one, though frequently by a pretend payment.
Chapter III, Part V, p. 1012. - The Wealth of Nations (1776) - Book V