By J. David Goodman, New York Times

NEW YORK — Faced with a Republican president-elect willing to draw hard lines on immigration, policing and funding for social programs, Mayor Bill de Blasio in a formal address on Monday drew some of his own, presenting New York City as a national model of resistance and “a better way.”

De Blasio, a Democrat, vowed to mount a legal challenge if the federal government tried to create a registry of the nation’s Muslims. He promised to protect immigrant families threatened with deportation. He pledged that an aggressive stop-and-frisk policing policy would never return to New York.

“The president-elect talked during the campaign about the movement that he had built,” said the mayor, referring to Donald Trump and the huge rallies he led. “Now, it’s our turn to build a movement — a movement of the majority that believes in respect and dignity for all.”

The mayor’s 40-minute speech — billed as a major address and delivered to supporters, invited guests and 11 center rows filled with city workers at Cooper Union — echoed in theme and some content one that another Democrat, Gov. Andrew M. Cuomo, delivered a day before, also in Manhattan.

Cuomo, in his remarks at the Abyssinian Baptist Church in Harlem, said he would create a new unit of the State Police to investigate hate crimes, move to expand state human rights law and seek new funds to provide legal representation to immigrants. De Blasio, too, said he would provide immigrants with lawyers, working with the New York City Council to do so.

De Blasio’s speech, delivered as he has begun his own re-election campaign, included several instances of call-and-response with the friendly crowd drawn from the full panoply of New York diversity, both in the seats and on the dais. An openly lesbian Protestant chaplain from the fire department helped to open the gathering along with an imam from the police department.

De Blasio spoke from a lectern adorned with a hashtag — #AlwaysNewYork — meant to inspire tales of solidarity and pride in New York values. He reminded the audience that Trump defended those values in abstract on the campaign trail during the Republican primary contests.

“We ain’t changing,” de Blasio said, before listing his promises to defend New Yorkers from deportation, unconstitutional police practices and any cuts to federal funding for Planned Parenthood. “We will ensure women receive the health care they need.”

Former city lawyers said the mayor could rely on the federalism of the Constitution as well as established case law to challenge undesired programs from Washington. It could be many more months, if not years, before the issues would be resolved in court.

“There is important value in reassuring people that the city and the state maintain considerable sovereignty over its own policy,” said Victor A. Kovner, a partner at Davis Wright Tremaine and a former city corporation counsel.

The federal government may have broad authority over immigration, said Michael A. Cardozo, a partner at Proskauer who served as the corporation counsel under former New York City Mayor Michael Bloomberg, a Republican turned political independent. “But those laws do not give the federal government carte blanche to do whatever it wants with an immigrant.”

Since the presidential election provided a shock to residents in the city and in many areas of the state, de Blasio and Cuomo have offered similar messages, appealing to Trump’s New York roots while also presenting themselves as defenders of their constituents who are worried about a new administration that neither of them supported during the campaign.

The speeches were met with derision from state Republicans on Monday. Edward F. Cox, the chairman of the state Republican Party, in a statement accused both of a “naked and unseemly fight” to position themselves for a future presidential run.

“These two scorpions in a bottle are each trying to outdo one another with slanderous fearmongering hyperbole,” he said.

Asked about de Blasio’s attempt to calm fearful New Yorkers, Kellyanne Conway, a top adviser to Trump, mocked the mayor to reporters outside Trump Tower: “Fearful of the jobs he’s killed? Fearful of the bike lanes?”

That sentiment was repeated in the response to de Blasio’s hashtag, which for much of Monday provided a forum on Twitter for those opposed to his handling of the city to vent frustrations, as well as for supporters.

“Mayor de Blasio rolled over for the NYPD after they did a back-turning protest,” one user wrote. “You think he won’t roll over for Trump?”

“So proud to be a New Yorker,” another wrote. “They should both be impeached,” another said of the mayor and the governor.

Even with a shared antagonist in Trump, de Blasio and Cuomo have not been able to bridge the gap between them that, those close to both men say, has seemingly widened beyond repair. They have not held an event together since the election and have appeared content to go their own way in assuaging the concerns of New Yorkers, even as they end up finding very similar ways of doing so.

“We will stand up and say, ‘Yes we are black, white and brown — but we are one,'” Cuomo said in his speech.

De Blasio said in his remarks the next day, “To all Latinos who heard their culture denigrated — we stand by you.”

“Yes we are Christian, Muslim and Jews, but we are one,” Cuomo said.

“To all the Muslims who have heard their faith belittled — we stand by you,” de Blasio said.

“And that is the New York way,” Cuomo said.

“We are always New York,” de Blasio ended.

To Learn More:

New York Appeals Court Calls for End to Police Stop-and-Frisk Tactics (by Rose Bouboushian, Courthouse News Service)

            Conservatives Decide Trump Qualifies as a Fascist (by Noel Brinkerhoff, AllGov)

Donald Trump Has a Plan for Deporting Millions of California Illegal Immigrants (by Ken Broder, AllGov California)