When James M. Buchanan began work in the 1940s, he enthusiastically adopted the prevailing positivistic methodology. Over the next forty years, his attachment to positivism weakened and, in his work on public debt, Buchanan gradually added an ethical dimension. His work on ethical aspects of debt was extended to consideration of public default. These issues have gained prominence again with the rise of public deficits since 2008 in various countries. It is likely that public debt in various countries (including the United States) will become unsustainable and that (open or concealed) default will follow. The morality of default, however, has not been openly debated. The current crisis must awaken a public debate on the ethics of public deficits and the need for legal limitations on public deficits and debt. Buchanan’s analysis of the ethics of public deficits, public debt, and public default should play a part in that debate.