Last week, one week after the first anniversary of Neil Gorsuch’s ascension to the Supreme Court, he delivered an opinion that was excellent as it pertained to the case at issue and momentous in its implications pertaining to the institutional tangle known as the administrative state.

If he can persuade his fellow court conservatives to see why they were mistaken in disagreeing with him, and if he can persuade his liberal colleagues to follow the logic of their decision with which he concurred, the judiciary will begin restoring constitutional equilibrium. It will limit Congress’ imprecise legislating that requires excessive unguided improvising by all those involved in seeing that the laws are “faithfully” executed.

In 1992, when James Dimaya, a Philippine citizen, was 13, he became a lawful permanent resident of the United States, where, unfortunately, his behavior has been less than lawful: In 2007 and 2009, he was convicted of residential burglary. The Department of Homeland Security says he should be deported because he committed a “crime of violence,” hence covered by a portion of immigration law that, after listing specific crimes (rape, murder, etc.), adds a catch-all category of crimes involving “a substantial risk that physical force against the person or property of another may be used in the course of committing the offense.”

How are judges supposed to apply this?

Writing for the majority in a 5-4 decision — and joined by Ruth Bader Ginsburg, Stephen Breyer and Sonia Sotomayor (with Gorsuch concurring in the judgment and much of the opinion) — Elena Kagan wrote: The law’s category, a “crime of violence,” is so indeterminate (“fuzzy,” she said) that deporting Dimaya under it would violate the Constitution’s “due process of law” guarantee. Vague laws beget two evils that are related: They do not give citizens reasonably clear notice of what behavior is proscribed or prescribed.

And they give — actually, require of — judges and law enforcement officials excessive discretion in improvising a fuzzy law’s meaning. In agreeing with this (and disagreeing with John Roberts, Anthony Kennedy, Clarence Thomas and Samuel Alito), Gorsuch wrote:

Vague laws “invite the exercise of arbitrary power” by “leaving the people in the dark about what the law demands and allowing prosecutors and courts to make it up.” The lack of “precise and sufficient certainty” (criteria stipulated by the English jurist William Blackstone, whose writings influenced the Constitution’s Framers) invites “more unpredictability and arbitrariness” than is constitutional.

Furthermore, the crux of America’s constitutional architecture, the separation of powers, is implicated. All legislative power is vested in Congress. The judicial power, Gorsuch wrote, “does not license judges to craft new laws” but only to discern and follow an existing law’s prescribed course.

With the fuzzy “crime of violence” category, Congress abdicated its “responsibilities for setting the standards of the criminal law.” So, allowing vague laws would allow Congress “to hand off the job of lawmaking.” Hence such laws not only illegitimately transfer power to police and prosecutors but also would “leave it all to a judicial hunch.”

The principle Gorsuch enunciates here regarding one provision of immigration law is a scythe sharp enough to slice through many practices of the administrative state, which translates often vague congressional sentiments into binding rules, a practice indistinguishable from legislating. Gorsuch’s principle is also pertinent to something pernicious concerning which he has hitherto expressed wholesome skepticism: “Chevron deference.”

This is the policy (named for the 1984 case in which the Supreme Court propounded it) whereby courts are required to defer to administrative agencies’ interpretations of “ambiguous” laws when the interpretations are “reasonable.” Gorsuch has criticized this emancipation of the administrative state from judicial supervision as “a judge-made doctrine for the abdication of judicial duty.”

It also is an incentive for slovenly lawmaking by a Congress too lazy or risk-averse to be precise in making policy choices, and so lacking in institutional pride that it complacently sloughs off its Article I powers onto Article II entities. Gorsuch wants Article III courts to circumscribe this disreputable behavior.

Gorsuch represents the growing ascendency of one kind of conservative jurisprudence, “judicial engagement,” over another kind, “judicial deference.” Many conservatives have embraced populism where it least belongs, in judicial reasoning. They have advocated broad judicial deference to decisions because they emanate from majoritarian institutions and processes. Progressives favor such deference because it liberates executive power from congressional direction or judicial supervision.

Gorsuch, a thinking person’s conservative, declines to be complicit in this, which raises this question: When has a progressive justice provided the fifth vote joining four conservative colleagues?