Strangely enough, the higher the public debt ratio, the more the countercyclical stabilisation of the economy must be done through fiscal policy

Countercyclical stabilisation of the economy can be achieved using either fiscal or monetary policy. But if the public debt ratio is high, long-term interest rates must be stable to avoid a public debt crisis, or at least an extremely restrictive fiscal policy if interest rates rise. And if interest rates cannot rise, they also cannot be lowered if activity declines. In this configuration, where the high public debt ratio significantly limits the extent of possible changes in interest rates, it is with fiscal policy that the economy must be stabilised countercyclically, even if the public debt ratio is very high.