The larger lesson here is about policy. The original sin—and it was nearly global—was to revive the Keynesian economic model that had last cracked up in the 1970s, while forgetting the lessons of the long prosperity from 1982 through 2007. The Reagan and Clinton-Gingrich booms were fostered by a policy environment for most of that era of lower taxes, spending restraint and sound money. The spending restraint began to end in the late 1990s, sound money vanished earlier this decade, and now Democrats are promising a series of enormous tax increases.

Notice that we aren’t saying that spending restraint alone is a miracle economic cure. The spending cuts now in fashion in Europe are essential, but cuts by themselves won’t balance annual deficits reaching 10% of GDP. That requires new revenues from faster growth, and there’s a danger that the tax increases now sweeping Europe will dampen growth further.

President Obama’s tragic mistake was to blow out the U.S. federal balance sheet on spending that has produced little bang for the buck. The fantastical Keynesian notion (the “multiplier”) that $1 of spending produces $1.50 in growth was long ago demolished by Harvard’s Robert Barro, among others. That $1 in spending has to come from somewhere, which means in taxes or borrowing from productive parts of the private economy. Given that so much of the U.S. stimulus went for transfer payments such as Medicaid and unemployment insurance, the “multiplier” has almost certainly been negative.