He would be fingerprinted. He would be photographed. He could even be handcuffed.
And if Donald J. Trump is indicted by a Manhattan grand jury in the days ahead for his role in a hush money payment to a porn star, the former president of the United States of America will be read the standard Miranda warning: He will be told that he has the right to remain silent and the right to an attorney.
These are among the routine steps for felony arrests in New York. But the unprecedented arrest of a former commander in chief — one whose devoted supporters once staged a violent attack on the Capitol — will be anything but routine.
Last week, senior officials from the district attorney’s office and the state agency that runs the courts had preliminary discussions to plan for a possible indictment and arraignment. So did officials from the Police Department, which patrols the streets outside the Lower Manhattan courthouse, and the court officers, who handle security inside the Criminal Courts Building, where Mr. Trump would be arraigned.
And on Sunday, more than a dozen senior Police Department officials and two of the mayor’s top public safety aides held a virtual meeting to discuss security, staffing and contingency plans in the event of any protests, one person with knowledge of the meeting said.
That meeting followed a call from Mr. Trump himself, in a post on his site Truth Social on Saturday morning: “PROTEST,” he exhorted his supporters. “TAKE OUR NATION BACK!”
The former president’s rallying cry, with an indictment looming, conjured up memories of the Jan. 6, 2020, assault on the Capitol.
Security is also a looming issue in the office of the Manhattan district attorney, Alvin L. Bragg, a Democrat who is the first Black person to lead the office. Mr. Trump has lashed out at the district attorney, calling him a racist and saying his investigation is politically motivated.
Understand the Events on Jan. 6
Mr. Bragg and one of his top aides have already been the targets of threats on Mr. Trump’s social media platform. In an email to staffers on Saturday, first reported by Politico, Mr. Bragg assured prosecutors and other staff that he had been coordinating with the Police Department and court officials to ensure their safety.
“We do not tolerate attempts to intimidate our office or threaten the rule of law in New York,” he wrote. “Our law enforcement partners will ensure that any specific or credible threats against the office will be fully investigated.”
Mr. Bragg’s security detail, which is staffed by New York Police Department detectives, may expand in the wake of Mr. Trump’s Saturday post; already the police have evaluated risks to his personal safety, according to a person with knowledge of the matter. In the past, the police department has adjusted its staffing based on its own assessment of the risk to a district attorney, another person with knowledge said.
In the wake of Mr. Trump’s public call for action, there were scattered signs that his followers were planning to protest on his behalf. The New York Young Republican Club announced on Sunday that it would hold a “peaceful protest of Alvin Bragg’s heinous attack” on Mr. Trump at an undisclosed location in Lower Manhattan on Monday evening.
On Saturday afternoon, the far-right provocateur Laura Loomer, who lives in Florida, declared on Twitter that she was organizing a pro-Trump rally outside Mar-a-Lago, Mr. Trump’s private club and residence in Palm Beach, to “protest Alvin Bragg’s WITCH HUNT.” But hours later, Ms. Loomer deleted the tweet and encouraged people to attend Mr. Trump’s upcoming political event in Texas instead.
On Twitter over the weekend, the far-right influencer Jack Posobiec called for Mr. Trump’s supporters to launch a “MAGA strike” and withdraw their money from banks en masse in an apparent effort to harm the financial system. Other Trump supporters circulated the main telephone number of Mr. Bragg’s office on social media and encouraged people to call and demand that charges not be filed against Mr. Trump.
Far darker messages were posted on pro-Trump chat boards like Patriots.win, a website formerly known as TheDonald.win, according to a review of social media by the The New York Times and by Advance Democracy Inc., a nonpartisan, nonprofit organization that conducts public interest research. In its final report last year, the House select committee investigating Jan. 6 determined that TheDonald.win served as an important nexus for people to discuss and make plans for the Capitol attack.
In the hours after Mr. Trump’s message was posted on Saturday, some posters on Patriots.win, mostly writing under pseudonyms, called for people to join together to protect Mr. Trump.
“Surround Mar-a-Lago or wherever he currently is,” a person named “sir-coffee” wrote, “and prevent law-enforcement from entering.”
Other posters called for a violent response to Mr. Trump’s arrest and said they would welcome harm being done to Mr. Bragg.
“I’d celebrate someone taking out that criminal DA,” someone using the name “trauncher” wrote.
If Mr. Trump is indeed indicted and arraigned, it will be one of the most unusual and closely watched court proceedings in New York history. And accommodation may be made for the former president.
While it is standard for defendants arrested on felony charges to be handcuffed, it is unclear whether they will make an exception for Mr. Trump because of his status. Most defendants have their hands cuffed behind their backs, but some white-collar defendants who are deemed to pose less of a danger have their hands secured in front of them.
After an arraignment, Mr. Trump would likely be released on his own recognizance because an indictment likely would contain only nonviolent felony charges; under New York law, prosecutors cannot request bail in most such cases.
Mr. Trump will almost certainly be accompanied at every step of the process — from the moment he is taken into custody until his appearance before a judge — by armed agents of the United States Secret Service, who are required by law to protect him at all times. Security in the courthouse is provided by New York State court officers, an agency with which the Secret Service has worked in the past. The chief spokesman for the Secret Service, Anthony J. Guglielmi, said he could not comment on any security arrangements for the former president.
It may take several days for the former president to appear at the courthouse. Once he has been indicted, prosecutors are expected to contact the former president’s defense lawyers to negotiate his surrender, a common practice in white-collar investigations when prosecutors have been in touch with defense attorneys.
Some lawyers working for Mr. Trump, who is running for president a third time, have said he will surrender to face the charges and fly from his Florida estate to New York for the arraignment.
The former president has made it clear he plans to use the charges as part of a campaign strategy to rile up his base.
Surrender, some might argue, is not in the confrontational former president’s DNA, and he often seems to relish antagonizing and attacking the prosecutors who have investigated him.
In the unlikely event that the former president refuses to surrender, he would put Gov. Ron DeSantis of Florida, his leading but undeclared rival for the Republican nomination, in an awkward political position. Under law, the role of Mr. DeSantis would be essentially ministerial and he would have few legal options other than approving an extradition request from New York.
Still, if New York prosecutors sought Mr. Trump’s extradition, Mr. DeSantis would face an unenviable dilemma. He would be compelled to choose between authorizing an arrest warrant for Mr. Trump and inflaming his base, or attempting in some way to aide his Republican rival, and possibly face legal action as a result.