Ms. Ogg said Mr. Trump’s law enforcement agenda would not prompt disagreement, but did not necessarily reflect new concerns. “No one in law enforcement is going to take a position against protecting law enforcement officers — but I think promoting equal justice and equal protection for everyone is the job of district attorneys, and our leadership,” she said. Mr. Trump has been silent about fatal police shootings of unarmed civilians — which until recently had monopolized conversations about criminal justice. Instead, he has spoken about the need for more aggressive policing to stem violent crime, including a threat to “send in the Feds” to quell the growing rate of homicides in Chicago.

Some police chiefs said they are reserving judgment until there is more meat on the bones of the administration’s plans. “Hopefully, they are going to seek our practical advice,” said Edward A. Flynn, Milwaukee’s police chief, who also heads the legislative committee of the Major Cities Chiefs Association. “That to us is key. We don’t want any more policy bromides grounded in campaign promises. We want ideas grounded in practical wisdom about how to protect our cities.”

Still, a number of chiefs — and perhaps the vast majority of lower-ranking officers — say they are basking in the glow of Mr. Trump’s positive attention after feeling under siege during the Obama administration. “Law enforcement in general was painted with a very broad brush,” said Michael J. Bouchard, the sheriff of Oakland County, Mich. “The idea was that policing was broke, and I think that was a false dialogue.”

Unions agreed. “I can promise that if we have a president who is speaking about protecting the lives of police officers, that the membership is going to be supportive of him,” said Chuck Canterbury, the president of the Fraternal Order of Police. “No police officer took an oath that said, ‘I agree to support and defend the Constitution and to get my butt whipped.’” Michael A. Ramos, the president of the National District Attorneys Association and the chief prosecutor in San Bernardino County, Calif., hailed the shift in emphasis, saying the pendulum had swung “way too far” toward being “soft on crime.”

Law enforcement leaders responded more positively to Mr. Trump’s order to ratchet up the fight against organized crime cartels, which operate through intermediaries in even the smallest American cities through the sale of heroin, methamphetamine, and other drugs.

But Darrel W. Stephens, the executive director of the Major Cities Chiefs Association, said the nation also needed to address its appetite for drugs: “We must do everything we can to stop the flow of drugs into our country, but doing so would not solve our substance abuse problem.”