Public Debt: How to Distinguish Good From Bad?

Not all debt is equal. Debt taken on to finance investment, the energy transition, education, innovation, or defence can prepare future growth and strengthen collective resilience. By contrast, debt accumulated to avoid making trade-offs, sustain inefficient spending, or artificially prolong fragile equilibria can become a lasting source of vulnerability.

But where should the line be drawn between useful and harmful debt, and according to which criteria? This session aims to reopen a crucial debate at a time of rising interest rates, demographic ageing, and massive public financing needs. Should debt be assessed by its level, its cost, its use, or the political credibility of the trajectory that accompanies it? And to what extent can harmful debt crowd out or contaminate useful debt?
A debt that appears sustainable on paper can become explosive if trust erodes, while high debt levels can remain acceptable if they finance productive capacity and follow a clear horizon. At what point does debt cease to be a tool of stabilisation and investment and become an economic, even generational, threat? In short, the real issue is not only the volume of debt, but the quality of the future it allows or fails to finance.