Presidential elections have consequences, and this one will affect New York City more than any in recent memory. This isn’t a comment on the candidates or the nationwide political tone, but on the simple fact that the winner of this election, Donald J. Trump, lives in New York City. And not just in New York City, but on Fifth Avenue in Midtown Manhattan, home to one of the world’s densest concentrations of humanity and traffic bedlam.

Fifth Avenue’s five lanes run past landmarks like the New York Public Library, the Empire State Building and Rockefeller Center, as well as numerous cathedrals of commerce, tourism and high-end retail. Because the avenue is such a popular destination, retail floor space there rents for $3,000 per square foot a year, the highest price in the world, more than double the cost of similar space along the Champs Élysées. It seems appropriate that gold is a popular color for building facades on Fifth.

Fifth Avenue at 56th Street is the site of Mr. Trump’s apartment in Trump Tower, which has rapidly turned into a fortress of Secret Service agents and heavily armed police officers surrounded by curious tourists, camera crews and protesters. They join the usual shoppers, workers and other pedestrians on what were already crowded sidewalks, and often spill into the street. This has significantly slowed traffic, and security concerns have forced the closing of side streets.

While Mr. Trump has said he will move into the White House, his wife and youngest child plan to wait until at least the end of the school year. During the campaign, Mr. Trump was known for flying home late at night so that he could wake up in his own bed, and he has said that he plans to return to the city frequently. If he chooses to stay even part of the week in New York, Trump Tower will become a de facto presidential residence and seat of global power.