The Lady Tam says it so very well –
Any money that the government “pumps into” the economy to “boost” it had to be pumped out of the economy in the form of taxes in the first place. Why is this so hard to understand? You can’t raise the water level in a swimming pool by siphoning its contents from the deep end to the shallow end, nor can you build a wall higher by removing bricks from the bottom and putting them on top. Why is this extremely simple fact so terrifically difficult for otherwise smart people to grasp?