Mercosur: un camino a la apertura o la consolidación de un bloque cerrado?

The MERCOSUR is an imperfect custom union whose Common External Tariff (CET) is lower than the one that each member applied before 1991. From 1990 to 1994 regional trade grew, and the patterns of trade changed. The aim of this paper is to analyze if the countries welfare and productive efficiency will improve, or if the productive inefficiency of each member will be protected because of MERCOSUR. In order to analyze this issue we perfomed three differents experiments using the GTAP a multicountry Applied General Equilibrium Model. The first experiment simulates a unilateral tariff reduction resembling the trade liberalization results of the CET. The second experiment supposes that the MERCOSUR countries remove all the tariffs on regional trade without changing the external tariffs. Finally, in the third experiment both policies are implemented. In the three experiments, regional trade increases as a consequence of trade liberalization inside a "natural block", as a MERCOSUR. Welfare in MERCOSUR countries also increases in the three experiments. The best policy for Argentina is unilateral trade liberalization, represented by the first experiment. However, the best one for Brazil, is the unilateral liberalization plus regional liberalization (represented by the third experiment).