The decision the Court handed down this morning, narrowing the deference an executive agency may demand for its construction of an ambiguous statute, is being treated in some quarters as a revolution. It is not. It is a clarification — and an overdue one — about the constitutional question that has sat quietly behind a half-century of administrative practice.

That question is this: when a statute is ambiguous and an executive agency promulgates a rule under its general authority, has the agency, in effect, written law? If so, by what authority? The Constitution gives the legislative power to Congress. It gives the executive power to execute. It nowhere contemplates a third power, lodged between the two, by which an unelected official may finalize the policy choice the legislators themselves declined to make.

The doctrine that emerged in the 1980s — that courts owed deference to the agency's reasonable construction of an ambiguous statute — was, in its time, a sensible accommodation to the complexity of modern government. I do not impugn the judges who fashioned it. What I observe is that the doctrine, as practiced, has tended to relieve the legislature of the discipline that ambiguity should impose. A statute insufficiently clear was, under the old practice, a statute the executive could complete; a statute insufficiently clear is, under the new practice, a statute the legislature must repair.

The proper response to today's decision is not for Congress to lament the loss of its delegate. It is for Congress to write more carefully — and where it has written carelessly, to amend. That is the body the Constitution charges with this work, and the body the citizens elect for it.

I anticipate two objections. The first: that this hands too much power to the courts. To which I answer: not at all. A court that says "the statute does not authorize this rule" is not legislating; it is reading. The legislature retains every power to write the statute differently. The second: that complexity demands expertise the legislature cannot supply. To which I answer: the legislature may consult, must consult, ought to consult. But the choice — the legal force of the rule that binds the citizen — must be theirs. Otherwise the citizen is bound by the unaccountable, which the Constitution was framed to prevent.

The Court did its work today. The Congress now has its work to do.