Precisely the same arguments have been applied to the downfall of the
interwar gold exchange standard. The interwar system, which depended for
liquidity on gold, dollars, and sterling, was if anything even more susceptible
than its post-World War II analog to destabilization by the operation of
Gresham’s law. As noted above, the legacy of the Genoa conference encouraged
central banks to accumulate foreign exchange. Promoting the use of exchange
reserves while attempting to maintain gold convertibility threatened the system’s
stability for the same reasons as under Bretton Woods. But because foreign
exchange reserves were not then concentrated in a single currency to the same
extent as after World War II, it was even easier under the interwar system for
central banks to liquidate foreign balances in response to any event that
undermined confidence in sterling or the dollar. Instead of initiating the relatively
costly and complex process of acquiring gold from foreign monetary authorities
in the face of at least moral suasion to refrain, central banks needed only to
swap one reserve currency for the other on the open market. Gresham’s law
operated even more powerfully when gold coexisted with two reserve currencies
than with one.