Though the potential threats are numerous, former NYPD bomb squad detective Kevin Barry said the royals have one very strong asset, beyond tight security.
"What they also have is incredible public support for the royal family and a strong 'see something, say something' attitude," he said. "They have done this before, but it has been a number of years. It's like the NYPD doing a New Year's Eve gathering."
Trotter believes his men are up to the challenge.
"It will be an exhausting day for the officers in this room," Trotter said of the men in police command. "It will be a long, arduous day, but we hope very happy day at the end of it."