In the simplest terms, Modern Monetary Theory (MMT) posits that a sovereign country with the ability to print its own currency should do so. This theory laughs at the notion that the growth in debt of a sovereign nation results in risk of default and thus too much debt is bad. The main speed limit imposed on the quantity of debt for MMT-ers is inflation. As long as there is no inflation, the theory demands larger and larger credit expansion and money printing. For countries with their own printing presses, such as the United States, Japan and China, the theory provides cover for government spending plans based on lots and lots of borrowing. For regions such as the Euroland, where is there is no fiscal union (yet), the European Central Bank is providing MMT of a sorts by bidding up bonds of the weaker countries at nosebleed prices using the credit of the more creditworthy countries (Source: ECB APP).