There was an interesting if not ego-centric interchange last week involving the New Keynesian economist Paul Krugman and others about whether the sort of macroeconomic policy positions one takes is more motivated by ideological motives (about the desirable size of government) rather than being evidence-based. Apparently, if you support austerity it is because you really just want smaller government and vice versa. This is an oft-stated claim made by conservatives. That if you support fiscal stimulus and government regulation that you are automatically in favour of big (intrusive) government. The point is not valid. Whether one supports a larger proportional government or smaller is a separate matter to understanding how the monetary system functions and the capacities and options available to the government. Modern Monetary Theory (MMT) provides the basis for that understanding but not a prescription for a particular size of government.