Harlan Cohen raises an important caution against being swept up in the attraction, indeed intellectual comfort, of an intellectual grand narrative that can give apparent coherence to a topic as broad-ranging and heterogeneous as international law in the Supreme Court. The point is very well taken, particularly as it runs to the framing of historical periods; the device of historical periods is useful - essential even - to a point, but only if it is taken as the starting point for sorting things out and not the final arbiter of interpretation, especially on any particular matter.
That said, there is more than simply an organizational imperative in asking some framing questions. I'd like to raise a couple of them here, as a preface for the kinds of issues that most intrigue me in looking at this marvelous study. They are not in any logical order, and one might easily argue that I've followed a kind of narrative imperative in the ones I've chosen, but they still seem to me important in practically any kind of historical study of this area.