WASHINGTON — President Trump on Monday assailed a broad movement to defund police departments, invoking the kind of pro-police language that won him support with the law enforcement community in 2016 and ignoring the calls for reform that have helped shape this election.

Democrats “want to defund, and they want to abolish,” Mr. Trump told a panel at the White House composed of people who have had positive interactions with the police. The president also said that Democrats were engaging in an “anti-cop crusade” while violent crime was rising in the cities they controlled.

With Mr. Trump facing an outcry over the threats he has made to protesters calling for racial equality and police reform efforts, his remarks on Monday were part of an effort to embrace law enforcement — and to move away from more explicitly racist language — as polls show him lagging behind Joseph R. Biden Jr., his presumptive Democratic challenger.

That has meant targeting police reform efforts supported by Democrats, such as shifting funding from police departments to social services like mental health and substance abuse counseling. Mr. Trump has called the defunding efforts a fad, but last month, he issuedan executive order outlining a series of overarching principles meant to encourage — but not mandate — departments to alter their behavior.

The president also painted a dark picture of the United States should Mr. Biden win.

“The radical politicians are waging war on innocent Americans,” Mr. Trump said. “If that’s what you want for a country, you probably have to vote for Sleepy Joe Biden because he doesn’t know what’s happening, but you are not going to have that with me.”

While recent polls have shown growing support among Republicans and Democrats for instituting police reform efforts — including banning chokeholds — after George Floyd, a Black man in Minneapolis, was killed in police custody, most Americans reject the idea of defunding police departments.

Mr. Trump and his campaign have tried to accuse Mr. Biden of supporting efforts to defund the police, but Mr. Biden has actually opposed them. The former vice president’s spokesman has said he supported the need for an “urgent” overhaul after several police killings of Black men and women.

The president started on his theme on Twitter on Monday by declaring that the police “must take a stronger stand with the Radical Left politicians that are treating them so badly, and so disrespectfully.”

During the White House panel, Mr. Trump blamed Democrats for upticks in crime in major cities, including New York and Chicago. Then he again targeted protesters, criticizing them for painting a Black Lives Matter sign outside Trump Tower in New York, something that made him seethe when he first saw it on television.

“They ought to spend their time doing something else,” Mr. Trump said, adding, “Last month, over 300 people were shot.”

The president’s count was not accurate, but the 205 shootings in June in New York were the highest for that month since 1996, the police said. And New York surpassed 400 shootings in the first half of the year for the first time since 2016, with 528 by the end of last month.

Matthew J. Hickman, a criminal justice professor at Seattle University, said that Mr. Trump and his administration were leaning into a campaign tactic of supporting police officers and calling for law and order, strategies that have been around since the Nixon era.

But Mr. Hickman pointed out that the president’s efforts have been undercut by his threatening language, and that his requests for the police to toughen their responses to protesters have led to criticism from police chiefs in Chicago, Houston and elsewhere.

“Any police executive with a head on their shoulders rejects this idea that they somehow need to be tougher on protesters,” Mr. Hickman said, citing as an example Art Acevedo, Houston’s police chief, who last month publicly criticized Mr. Trump’s comments. “The ‘law and order’ thing is nothing new, but what is new in the Trump era is police chiefs pushing back on that.”

Mr. Trump was also asked by a reporter about how he could encourage Americans to support law enforcement when his decision to commute the sentence of his longtime friend and former campaign aide Roger J. Stone Jr. appeared to undermine his own Justice Department.

“Well,” Mr. Trump said, “if you look back on it, this was an investigation that should have never taken place.”