Ludwig von Mises on Santa Claus economics

At the bottom of the interventionist argument there is always the idea that the government or the state is an entity outside and above the social process of production, that it owns something which is not derived from taxing its subjects, and that it can spend this mythical something for definite purposes.  This is the Santa Claus fable raised by Lord Keynes to the dignity of an economic doctrine and enthusiastically endorsed by all those who expect personal advantage from government spending. 

~ Ludwig von Mises, Human Action, p. 744

Ludwig von Mises on the limits of interventionism

An essential point in the social philosophy of interventionism is the existence of an inexhaustible fund which can be squeezed forever.  The whole system of interventionism collapses when this fountain is drained off: The Santa Claus principle liquidates itself.

~ Ludwig von Mises, Human Action