Given the scope of the current crises, several arguments in favor of discretionary fiscal policy have been put forward. First, since the output gap is expected to remain negative for a longer period of time, the well-known implementation lag of discretionary fiscal policy is currently less problematic. Second, in "normal" times, fiscal policy supports monetary policy in smoothing the business cycle via automatic stabilizers.
This has worked quite well over the last 25 years. Yet, these are not "normal" times. Although automatic stabilizers still work, they are not large enough to prevent a severe economic downturn. Moreover, they have been weakened through structural reforms like reductions in the progressivity of tax systems and a decrease in the public expenditure-to-GDP ratio.