The United States Constitution is, in form and fact, a kind of fiduciary instrument, and government officials acting pursuant to that document are subject to the background rules of fiduciary obligation that underlie all such documents. One of the most basic eighteenth-century fiduciary rules was the presumptive rule against subdelegation of discretionary authority. The rule was presumptive only; there were recognized exceptions that permitted subdelegation when it was specifically authorized by the instrument of agency, when it was validated (...) by custom or tradition, and when it was necessary for accomplishment of the agent’s authorized purposes. To what extent might that third exception justify broad subdelegation of legislative authority by Congress to administrative agencies? Part of the answer, which is beyond the aims of this essay, depends on ascertaining the nature of the job entrusted to Congress under the Constitution, which means ascertaining the scope of Congress’s delegated powers. Another part of the answer depends on the extent to which expertise can and may serve as justification for entrusting others with tasks with which one has previously been entrusted. What would a responsible fiduciary approach to expertise—whether for purposes of advice or subdelegation—look like in the modern administrative state? The answer requires a careful examination of the idea of expertise and how it can be applied, and misapplied, in modern governance. This essay offers only the briefest introduction to that problem by trying to frame the questions that responsible fiduciaries need to ask before subdelegating authority. Such questions include: (1) What are the limits of the principal’s own knowledge? (2) What reason is there to think that gaps in that knowledge can, even in principle, be filled by experts? (3) Will application of expert knowledge lead in any particular instance lead to better decisions, given the ubiquitous problem of second-best? and (4) Have you picked the right experts, and will they actually apply expertise rather than using their claim to expertise as a cover for pursuing other goals? These questions in the context of the modern administrative state are just one aspect of a broader problem of nonexperts trying to evaluate—both before and after the fact—the work product of experts. (shrink)