Two assertions about exchange rate regimes circulate with some frequency in policy circles. The first, the hypothesis of the excluded middle, holds that authorities must either choose perfectly floating exchange rates (preferably anchored by an inflation target for the central bank) or a hard...

The view that modest alterations to monetary policy have vast consequences for national economies would seem to be inconsistent with theory and evidence. Most modern economic models (represented authoritatively by Woodford 2005) offer limited scope for policy surprises. The basic logic is that...