Let me add something on a personal note: What I learned during my years in government is that in normal times discretionary fiscal policy is surely not an advisable tool of stabilisation. Far too many lags exist that reduce the effectiveness of expansionary measures.
Moreover, looking at the long term, we have to bear in mind that political economy mechanisms bias fiscal policy towards incurring deficits. However, in an exceptional crisis things are slightly different and it cannot be denied that discretionary fiscal policy had a stabilising effect.