In his essay Of Public Credit, David Hume argues against the institutionalization of public credit. Contrary to what is commonly believed, I claim Hume’s analysis of public credit is sound and it is an example of his worst-case thinking. Through textual and contextual analysis, I show for Hume public credit brings catastrophic results because men are knaves, systematically biased, and unlucky. Public credit is an appropriate institution to stimulate the economy only if men are perfect and perfectly predictable. But they are not. For Hume, considering the worst-case rather than the best-case helps prevent potential disasters. Public credit should therefore be avoided.