Marc Ambinder, a fellow at the Annenberg School of Communications and Journalism at the University of Southern California, covered national security and the White House for National Journal.

(Photo illustration by Chris Barber for The Washington Post)

Donald Trump is a creature of New York. He ran against Washington and called it “a swamp.” During his campaign, he often flew home late at night so he could wake up in his own bed. His 10-year-old son is enrolled in a Manhattan private school. So it’s no wonder Trump is reportedly considering spending time in New York whenever he is able — presumably on weekends.

If so, his home, in the penthouse of Trump Tower, on E. 56th Street and Fifth Avenue, will be the epicenter of an iron curtain that will wall off much of Midtown from the rest of the city. Creating a permanent, sterile environment inside a 58-story, multi-occupancy building on one of the busiest streets in one of the busiest cities in the world poses an unprecedented challenge for the Secret Service and the military.

No city on Earth is better prepared to host a presidential visit than New York: The police department works seamlessly with the Secret Service these days, and Manhattanites are used to traffic jams. But to accommodate a more regular presidential presence, the daily routines of ordinary New Yorkers who live in, work near or commute through a five- to 10-block radius of Trump Tower will change. They will not be able to move freely; sometimes they won’t be able to move at all. Whenever a president moves, everything nearby freezes.

This past week, the Secret Service and the NYPD began to draw up a security blueprint to protect the soon-to-be-president while minimizing disruption. (Secret Service spokesman Marty Mulholland declined to comment for this story, citing the agency’s policy of not talking about protective operations.) But shielding Trump from harm is only one of many objectives. Ensuring that he can communicate with the military, world leaders, Congress and the American people at all times is just as vital, and these goals exponentially increase the number of people, objects and systems that surround a modern president.

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Consider the disruption that a routine, half-day presidential visit can have on New York. On May 30, 2009, President Obama fulfilled a campaign promise to take the first lady to the city for a date: just an intimate dinner in the Village and an August Wilson play on Broadway. The planning began in secret about nine days before the trip, one of the staffers involved told me. A Secret Service agent accompanied a presidential advance-team volunteer to the theater and asked the manager for four tickets — two for VIPs, two for Secret Service agents. Near an exit. “And who would these be for?” the manager asked. “We can’t tell you,” came the apologetic reply.

When the big night arrived, word had gotten out, and the NYPD shut down 44th Street for hours, snarling traffic. The Obamas arrived right on time, but a glitch in screening theatergoers through magnetometers meant that entry lines were long and slow. So the president had to wait outside in the rear while agents checked the remaining audience members for weapons.

In the end, the trip took three airplanes , three helicopters, about 100 federal security agents and dozens of police officers accruing overtime. It required secure telephones in secure rooms inside the theater and the restaurant. All for a night out.

So what about a regular presidential presence?

Start with the epicenter: Completed in 1983, the glass-enclosed Trump Tower was designed before New York became a prime target for terrorist threats. It’s a sturdy building, but it wasn’t constructed with security in mind.

President Donald Trump and his family are regularly spending time at Trump Tower in New York. Here are some changes needed to make that space secure. (Adriana Usero/The Washington Post)

From now until the end of Trump’s presidency, everyone who enters and exits the building will have to be vetted by the Secret Service, even if the Trumps aren’t there. At the very least, their names will be run through agency threat databases. The service will want to inspect every package that goes into the building and will insist that staffers — at every shop, restaurant and residence — be scanned with a hand-held magnetometer, which detects hidden metal. When Trump is there, all of their personal effects will probably be checked by bomb-detection dogs, too.

Trump’s office is about 30 floors below his apartment. In between and below are residences and offices owned or leased by other people, who have rights that the city and state of New York are obligated to enforce. (For instance, the federal government can’t evict or move tenants at will.) Celebrities such as Cristiano Ronaldo and Bruce Willis, who keep apartments in the building, will find themselves living in Trump’s bubble.

The Secret Service has a special unit that will defend Trump Tower’s electronic and cyber architecture from electronic attack. Occupants might have to surrender some privacy as agents look to monitor incoming phone calls and even Internet traffic. The White House Communications Agency will build a separate, air-gapped Internet to carry classified information inside the intranet of Trump Tower, and the White House Military Office (WHMO) will provide Trump’s residence and office with an uninterrupted supply of power. Can the building handle the infrastructure without displacing others? Can the penthouse windows handle up-armoring?

The WHMO will require significant new space of its own somewhere in the building. That means it will pay rent to its landlord — that is, to Trump, if the agency uses space that the Trump Organization owns. This would not be unprecedented; Vice President Biden charged the Secret Service to occupy a building on his property in Delaware. Government rules prevent the agency from accepting anything of significant value from a protectee, and land has value. During the campaign, Trump was able to recoup $1.6 million from the Secret Service because he flew on his own planes, and the agents, just like everyone else, had to pay for their seats.

Trump will need his own Sensitive Compartmented Information Facility at Trump Tower, so he can openly and safely discuss national security matters. The WHMO’s Presidential Contingency Programs Office, which supervises the highly secret continuity-of-the-presidency and continuity-of-government schemes, will probably have to revise its playbooks for catastrophic emergencies. While Trump is in residence, a helicopter has to be stationed somewhere close by so he can be quickly evacuated from Manhattan, and at least one airplane will always have to be kept fueled, on standby, waiting to take the president to a military base in the event of a crisis. Safe houses need to be opened, maintained and kept secret.

A contingent from the Uniformed Division of the Secret Service might have to move to New York to maintain the outer perimeter, and so might technicians who will protect the building’s air supply from a chemical or radiological attack. The service has a number of heavily armored cars and electronic counter-measure vans in a warehouse somewhere in the city, but it could decide that it wants Marines from HMX-1, the squadron that flies the president’s helicopters, to move up from Virginia full time.

A single presidential visit costs the Port Authority of New York and New Jersey, which runs the city’s airports, $100,000 to pull off. With repeated, regular trips, price tags, delays and frustrations will scale up, quickly. When Air Force One — which costs about $236,000 per hour to fly when fully loaded with pilots, passengers, security, gear and fuel — arrives at New York’s John F. Kennedy International Airport, the tarmac will be frozen for at least 15 minutes before it lands. That short delay will reverberate through the extremely crowded airspace over New York. And whenever Trump travels, hundreds of people will move with him. The NYPD will be on the hook for hundreds of hours’ worth of overtime each week.

Thanks to the barricades and blockages around Trump Tower, local businesses are already reeling from a mini-Trump recession. Henri Bendel, across the street from Trump Tower, shut its doors mid-afternoon at least twice this past week; there was not enough foot traffic to justify keeping the store open. The manager of Obicà, a fancy Italian restaurant in the IBM building, at 56th Street and Madison Avenue, told CBS News that sales were already suffering from the pre-inauguration traffic closures put in place by the police. Traffic in Midtown is always intense. It will get much worse.

Tourists, too, will find their experience of New York altered by the presence of a president. Weekend helicopter tours of the city are probably now a pleasure of the past. A temporary flight ban, instituted right after the election, will become permanent and will expand.

The challenges won’t end at Trump Tower. The president-elect has his favorite haunts. He is said to enjoy dining at Jean-Georges on Central Park West, for instance. But from a security standpoint, predictability means vulnerability. So the Secret Service will watch Trump’s frequent destinations, using counter-surveillance personnel to see if any ne’er-do-well is casing them. Protesters will probably tail Trump’s motorcade for a long time, so quick and quiet trips — “off the records,” they’re called — will be very hard to pull off, unless Trump sneaks out of the building. Just this past week, he escaped the press to have dinner unmolested at the 21 Club. But a presidential retinue is much larger, and the security protocols will be different.

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Never before has a president lived among other people on weekends. All decompress from time to time at their getaway spots, but these places have been discrete entities that could be secured without disrupting the lives of too many people around them. Richard Nixon’s beloved estate in San Clemente, Calif., was surrounded by about six acres of land in a gated community. The Kennedy compound in Palm Beach, Fla., bordered an ocean, which necessitated the presence of the Navy and Coast Guard, but otherwise it did not need an expanded security perimeter.

The Obamas spent most of their weekends in Washington. When the president wanted to get out of his prison, he would golf on a nearby military base, minimizing the disruption. Biden spent most of his weekends at home in Wilmington, Del. He took the Acela. So seamlessly did the Secret Service and Amtrak work together on security plans that unless you knew what to look for, you could take the train with the vice president and not know it.

Being commander in chief is difficult, so presidents need a respite. We can give Trump a break for wanting to go home, but he can give New Yorkers a break by acknowledging that his presence will require them to sacrifice on his behalf. Radio host Howard Stern, who broadcasts from the studios of Sirius Satellite Radio near Trump Tower, started his show Wednesday by quipping that, for New Yorkers, “it would be a lot easier for Trump to stay away from his apartment.” Stern said that his even driver, Ronnie Mund, who proudly voted for Trump, complained: “How the hell are you gonna get anywhere?”

[CORRECTION: An earlier version of this story said Trump Tower was on West 56th Street and 5th Avenue. Because it is on the east side of 5th Avenue, the building is on East 56th Street.]