The Asuncion Treaty is based on the doctrine of the reciprocal rights and obligations of the member states. MERCOSUR initially targeted free-trade zones, then customs unification and, finally, a common market, where in addition to customs unification the free movement of manpower and capital across the member nations' international frontiers is possible, and depends on equal rights and duties being granted to all signatory countries.
During the transition period, as a result of the chronological differences in actual implementation of trade
liberalization by the member states, the rights and obligations of each party will initially be equivalent but
not necessarily equal.
In addition to the reciprocity doctrine, the Asuncion Treaty also contains provisions regarding the most-favored nation concept, according to which the member nations undertake to automatically extend--after actual formation of the common market--to the other Treaty signatories any advantage, favor, entitlement, immunity or privilege granted to a product originating from or intended for countries that are not party to ALADI.