Marginal revolutionaries

POINT UDALL on St Croix, one of the US Virgin Islands, is a far-flung, wind-whipped spot. You cannot travel farther east without leaving the United States. Visitors can pose next to a stone sundial commemorating America's first dawn of the third millennium. A couple named “Sigi + Ricky” have added a memento of their own, an arrowstruck heart scrawled on the perimeter wall in memory of “us”.

Warren Mosler, an innovative carmaker, a successful bond-investor and an idiosyncratic economist, moved to St Croix in 2003 to take advantage of a hospitable tax code and clement weather. From his perch on America's periphery, Mr Mosler champions a doctrine on the edge of economics: neo-chartalism, sometimes called “Modern Monetary Theory”. The neo-chartalists believe that because paper currency is a creature of the state, governments enjoy more financial freedom than they recognise. The fiscal authorities are free to spend whatever is required to revive their economies and restore employment. They can spend without first collecting taxes; they can borrow without fear of default. Budget-makers need not cower before the bond-market vigilantes. In fact,...