The US “Twin Deficits”. A Reappraisal

Since the mid-1980s, an extensive empirical literature has investegated the relationship between the US fiscal and trade deficits without reaching any consensus. Two elements may account for these conflicting results. First, considering data in levels versus stationarized data has an impact on conclusions. Moreover, the link between the US next exports and govenment balance, whether stationarized or not, is unsteady. This lack of robustness may stem from changes in the relative contribution of demand and supply shocks in the US economy : demand shocks generate a positive correlation between trade and fiscal deficits while supply shocks imply a negative relationship between both series. In order to check empirical relevance of this intuition, I use a standard Real Business Cycle model. With varying estimated volatility ratios of supply and demand shocks, the model succeeds in matching the switching magnitude of the correlation between the US balance of trade and fiscal deficits over each sub-sample except the 1990s.