Trump recently shifted his official address to Mar-a-Lago in Florida, but the tower remains his first big success: the place where The Apprentice was shot and where he announced his candidacy for president in 2015.

“It’s his pride and joy,” the official said.

The helmeted cops with assault rifles and body armor posted by the entrance and backed by a host of Secret Service personnel could probably defend the tower should a team of gunmen try to storm it.

But the concrete barricades that line the curb would do little to protect it against a vehicle-borne bomb detonated outside the Fifth Avenue entrance.

“What do you do, close Fifth Avenue?” the official asked. “And if so, for how long?”