Quantitative easing: QE, or not QE?

THE conventional arms have run out. Central banks in America and Britain have long since pushed interest rates to close to zero. On July 5th the European Central Bank (ECB) joined them, slashing its rate on deposits to 0% and its main policy rate below 1%. A different sort of arsenal is now being deployed. Unconventional monetary policy covers everything from negative interest rates—now on offer...