“Where is the Len Bias moment?” asked Chuck Wexler, the executive director of the Police Executive Research Forum, referring to the college basketball star’s cocaine-overdose death in 1986, considered a starting point for a so-called national war on drugs.

“We’ve been at this for, now, four or five years, and the overdose numbers continue to go up,” he added. “What’s going to be the defining moment to move this in a different direction?”

To that end, Mr. Wexler brought scores of local law enforcement leaders together last month to confront a battle that J.Scott Thomson, the police chief in Camden, N.J., told them “we are still losing.” In an auditorium at 1 Police Plaza in Lower Manhattan, attendees spoke with prosecutors and public health officials of the new tactics and realignments the crisis has wrought.

They discussed the “good Samaritan” laws that grant overdose victims seeking medical help immunity from prosecution, and how sheriffs can get help for addicted inmates. But each idea seemed a friction point: How to tell a midlevel dealer from a user needing help? How to tie a specific drug to a death to bring a murder charge? How to choke off supply routes that begin beyond their borders? How to use more discretion on nonviolent drug violators when Attorney General Jeff Sessions is ordering the harshest possible charges in federal drug cases.

It is a complex crisis, with roots in years of overprescription and abuse of opioid pills, which hooked people around the nation, Mr. Rosenberg said. “Roughly four out of five new heroin users start out on prescription medication,” he said.

On the street, heroin can be one-fifth the price of opioid pills like hydrocodone and oxycodone. It is also a more plentiful substitute, Mr. Rosenberg said, and can be far more potent, particularly with the emergence of strains mixed with fentanyl and carfentanyl.

In New York City, Robert K. Boyce, the chief of detectives, saw overdose deaths hitting record highs in areas across the city. This as homicides dropped to 335 last year and traffic fatalities to 220. He created new teams of homicide and narcotics detectives to focus on how sales — usually of $10 bags or $100 bundles — occur via digital links, and “not on the street,” and added 84 investigators to the effort.