The city Health Department’s subway ad campaign reassuring hard-drug users that they can be “empowered” by “using safely” is not an isolated approach to the epidemic of overdose deaths. It’s part of a larger “harm reduction” movement based on the idea that the combination of decriminalization or outright legalization will reduce the tragic number of US overdose deaths — 100,000 last year. The ads are of a piece with the “safe-injection sites” inaugurated by the de Blasio administration.

But as evidence starts to come in from the real world, this Pollyannaish view deserves to be questioned.

Consider what’s happened in Oregon, where in 2020 voters approved a ballot measure to decriminalize hard drugs — and at the same time establish addiction treatment centers. Unconsidered was the possibility that making heroin and fentanyl legal — subject to a $100 fine that could be waived if one just calls a help hotline — might actually encourage more use.

Instead of harm reduction, OD deaths are climbing. At a hearing on the law, a state legislator from rural Eagle’s Pass reported a 700% hike in drug use and a 120% rise in overdose deaths. Oregon’s secretary of state told the hearing that “in many communities in Oregon we’ve seen the problem with drug addiction get worse.”

The harm-reduction movement needs to accept common sense: Acquiescence signals approval.

Advocates of decriminalization believe, as usual, that the problem is money. Spend more and we’ll see improvement! But what’s happening so far should put this whole movement on notice: You’re experimenting with human lives and the lives of families ruined by drug users.

Whether it’s the safe-injection sites in Harlem and Brooklyn or the decriminalization of cocaine and opioid possession in British Columbia (announced this week), advocates of the harm-reduction approach must be willing to accept evidence.

Accepting hard-drug use signals that public-health authorities believe they have no tools to reverse a public-health crisis, that they are giving up on thousands of citizens or embracing the misbegotten idea that one can be a productive drug addict.

Here’s another idea for the city Health Department: a subway campaign urging riders not to use drugs in the first place. Heavy-handed “Just say no” warnings may not be the right approach — but in a city filled with the most creative advertising firms in the world, we should not rule out a campaign that could change habits and lives.

It is ironic indeed that we see no such public-health campaign even as the state continues to run graphic portrayals of end-stage lung cancer and regrets from its victims that they ever took up smoking. A similar anti-drug campaign could include grief-stricken parents who have lost children to overdoses — and saw their potential snuffed out.

Government sends signals about what it is acceptable. From drug-decriminalization laws to the “Use safely” campaign, government is sending the wrong signal.

Howard Husock is a senior fellow at the American Enterprise Institute.