Brandon's view appears to be that all genuine causation is agent- as opposed to event-causation, but that (contra Malebranche) there are non-divine agents including perhaps material bodies. How then does Brandon fit together divine causation with natural causation? Is he a concurrentist like Freddoso? I myself argue that occasionalism is defensible in contemporary terms. A sketch of my position is presented in my article, "Concurrentism or Occasionalism?" (Amer. Cath. Phil. Quart., Summer 1996, pp. 339-359.) Not yet available on-line.
I wouldn't quite put my view this way myself, since I think the term 'agent causation' as it is used today actually only covers a small part of what was covered by the pre-occasionalist view of causation: it was an attempt, explicit in both Berkeley and Reid, to preserve that view for minds or spirits alone. And I think its current usage bears the clear marks of the restriction, which I do not accept; it is a carry-over from idealism. However, if this is all kept in mind, I could indeed put my view of causation that way, i.e., all genuine causation is agent-causation, where there are non-divine agents including material bodies. The result of this (when added to other things) is that I am, indeed, a concurrentist. Freddoso is a concurrentist along the specific lines of Suarez and Molina; my concurrentism doesn't have quite that specificity, so I'm just a generic concurrentist, one might say. I'll have to look up Vallicella's article; this whole area is of interest to me. (Freddoso's papers on the subject are quite good; I used his paper on secondary causation last year twice, once for Berkeley and once for Malebranche.)
In August I translated a passage from Malebranche on the issue of providence and causation, in which he lays out the field as he sees it, and why he rejects concurrentism. (The translation is somewhat literal, which is why there are commas everywhere - Malebranche likes balancing and counterbalancing clauses, so tends to mark every turn of the sentence with commas.)