Christian Burset (Notre Dame Law School) has an article coming out in vol. 74 of the Vanderbilt Law Review, forthcoming in 2021. Here's the abstract posted on SSRN for "Advisory Opinions and the Founders' Crisis of Legal Authority" (Notre Dame Legal Studies Paper No.200826):
The prohibition against advisory opinions is fundamental to our understanding of federal judicial power, but we’ve misunderstood its origins. Discussions of the doctrine begin not with a constitutional text or even a court case, but a letter in which the Jay Court rejected President Washington’s request for legal advice. Courts and scholars have offered a variety of explanations for the Jay Court’s behavior. But they all depict the earliest Justices as responding to uniquely American concerns about advisory opinions.
This Article offers a different explanation. Drawing on previously untapped archival sources, it shows that judges throughout the anglophone world—not only in the United States, but also in England and British India—became opposed to advisory opinions in the second half of the eighteenth century. The death of advisory opinions was a global phenomenon, rooted in a crisis of common-law authority.
Early modern English judges had routinely advised the Crown. This advisory role was politically fraught but doctrinally unproblematic thanks to a jurisprudential orthodoxy that treated judges’ opinions as evidence of a preexisting common law. Although this declaratory theory survived into the nineteenth century (and beyond), it began to fragment after 1750, as lawyers began to disagree about the nature of precedent. Those disagreements generated new pressure to clarify the weight of different kinds of legal authority. Most lawyers intuited that advisory opinions were less authoritative than decisions arising from litigation. But because bench and bar lacked a common theory of legal authority, they were unable to articulate a shared understanding of what respect was due to judges’ extrajudicial pronouncements. As a result, advisory opinions became dangerous, because the judges who issued them could not control how future readers might treat them. In response, judges sought to limit their advisory activity—first in England, then in British-controlled Bengal, and finally in the United States, whose judges inherited Britain’s contested and dynamic understanding of judicial power.
Further information is available here.