I present a minimalist analysis of the pronominal system of Portuguese compatible with the claim that pronouns are underlying determiners (Postal 1969, Raposo 1973), including the nominative and dative forms. Whereas the form o is a "pure" determiner (a [+minimal, -maximal] projection), the nominative and dative pronouns will be analyzed as [+minimal, +maximal] projections with a nominal feature already "incorporated " in their grammatical feature matrix. I also argue that, under Postal's theory, the ungrammaticality of sentences with an accusative clitic pronoun in Colloquial Brazilian Portuguese cannot be due to a loss of that lexical item, since the item is well and alive as an article (including as head of accusative DPs). Rather, the difference will be tracked down to the fact that the form ele lost its inherent (nominative) Case (which it maintains in European Portuguese), which puts it in direct competition with the form o. Considerations of economy, in the sense of Chomsky (1995), play an important role in this account.