Now, all the political engagement around heroin has helped create what Timothy Rourke, the chairman of the New Hampshire Governor’s Commission on Alcohol and Drug Abuse, says is an impetus for change, not unlike the confluence of events that finally produced a response to the AIDS epidemic. “You have a lot of people dying, it’s no longer just ‘those people,’ ” he said. “You have people with lived experience demanding better treatment, and you have really good data.”

A More Forgiving Approach

Among recent bills passed by the New Hampshire legislature in response is one that gives friends and family access to naloxone, the anti-overdose medication. Mr. Griffin, a few months after his daughter died, was among those testifying for the bill. It was set to pass in May but would not take effect until January 2016 — until Mr. Griffin warned lawmakers that too many lives could be lost in that six-month gap. At his urging, the bill was amended to take effect as soon as it was signed into law. It went into effect June 2.

Other parents like him have successfully lobbied for similar measures across the country. Almost all states now have laws or pilot programs making it easier for emergency medical workers or family and friends to obtain naloxone. And 32 states have passed “good Samaritan” laws that protect people from prosecution, at least for low-level offenses, if they call 911 to report an overdose. A generation ago when civil rights activists denounced as racist the push to punish crack-cocaine crimes, largely involving blacks, far more severely than powder-cocaine crimes, involving whites, political figures of both parties defended those policies as necessary to control violent crime.

But today, with heroin ravaging largely white communities in the Northeast and Midwest, and with violent crime largely down, the mood is more forgiving.

“Both the image and reality is that this is a white and often middle-class problem,” said Mr. Mauer of the Sentencing Project. “And appropriately so, we’re having a much broader conversation about prevention and treatment, and trying to be constructive in responding to this problem. This is good. I don’t think we should lock up white kids to show we’re being equal.”

So officers like Eric Adams, a white former undercover narcotics detective in Laconia, are finding new ways to respond. He is deployed full time now by the Police Department to reach out to people who have overdosed and help them get treatment.