Catherine LaCugna says that developments in Christology provide “an analogy for the project” of her book on the Trinity.  It’s a bad analogy from the getgo.

LaCugna notes that modern Christology has collapsed the distinction of Person and Work, ontology and function, or, what we might call the “ontological” and the “economic.”  Christology and soteriology are inseparable, and there is no “real distinction between being and function.”

Whatever we might say about that development, it can hardly provide a model for Trinitarian theology.  Christology is, by definition, about the economy; it is about soteriology because the incarnate Son is the Savior.  Reasoning from the developments in Christology, LaCugna suggests that we can make no “real distinction between the being of God and God’s relationship with all creation.”  Of course we cannot in Christology, for Christ is a creature (as well as Creator).  But that non-distinction is not at all obvious when talking about the Trinity, unless we’ve made a prior assumption that God cannot be without His creation.