This paper provides an analysis of Breton phrase structure and examines its consequences for the reformulation of the ECP in Rizzi (1990b). Particularly, I argue that subjects must be antecedent governed. I demonstrate that a number of aspects of Breton syntax, particularly subject agreement phenomena in V2 root clauses, are thus explained. In the course of the argument, I present an alternative to the standard analysis of a V2 language, in which I treat V2 not as an absolute characterization of a language containing certain rules, but rather as one relative to the instantiation of an abstract feature [Aff] (see Laka 1990) and the nature of C0 (Platzack 1986, Rizzi 1990a).