Madison Square Garden looked less like a basketball arena and more like a government compound on Monday, as law enforcement descended on Manhattan for Game 3 of the NBA Finals between the New York Knicks and San Antonio Spurs.

The reason? Donald Trump was coming to the Garden.

The President's attendance had transformed what would already have been one of the hottest tickets in the city into a full-scale federal security operation - and the moment you turned the corner onto Seventh Avenue, you felt every bit of it.

The police presence hit you immediately. It wasn't just a couple of officers, nor just a single patrol car parked at the curb. Instead, it was a swarm. Hundreds of cops, positioned at every conceivable entry point, lining the barriers - watching and waiting.

And those barriers - heavy, solid and industrial - ringed the arena like a fortress wall. MSG, one of the world's most recognizable venues, had been transformed overnight.

For those of us arriving with media credentials, the drama was only just beginning. 

The line stretched back further than expected, a slow-moving procession of press and broadcasters inching forward under the watchful gaze of law enforcement.

As you shuffled forward, the details of the operation became clearer.   

Officers patrolling the perimeter were not carrying standard-issue firearms. These were assault rifles - the kind of hardware you associate with military checkpoints or major international security operations, not a sporting event, however big.

The media entrance itself was nothing short of a full TSA experience transplanted from JFK to the middle of Manhattan. 

Bags were pulled open and searched with thoroughness, while metal detectors stood waiting for every single person - no exceptions, no fast lanes, no waving through.

Then came the police dogs sweeping bags and bodies with an efficiency that underlined just how seriously the authorities were taking the President's presence.

Nothing was getting through that line that wasn't supposed to.

The whole process took the best part of half an hour. Thirty minutes of queuing, shuffling, unzipping, removing, scanning and re-packing before you were anywhere close to the inside of the building.

But perhaps the most striking sight of the arrival experience was not the barriers, nor the rifles, nor the dogs. It was the group standing off to the side of the main entrance.

A large cluster of individuals - fitted with sharp suit and earpieces - were gathered in a tight formation outside the arena. Unmistakably, they were Secret Service. 

They moved differently to the uniformed officers around them, they watched differently and they made very clear, without saying a single word, that the most powerful man in the world was not far behind.

The speculation among fellow media members in the queue was immediate. The sight of that contingent on Eighth Avenue answered some questions and raised plenty of others.

To put all of this in context, the Knicks come into tonight's game leading this series 2-0, with the city of New York daring to dream about a championship that has been decades in the making. Trump chose quite the moment to show up.

New York does not do things quietly at the best of times but this was something beyond even the city's usual flair for the dramatic - Midtown Manhattan was on lockdown. 

By the time you eventually cleared security and made your way inside, there was already a strange sense that the night's real drama might not be confined to the hardwood.

One thing was certain before a single shot had been taken. Tonight, nobody was getting into Madison Square Garden who wasn't supposed to be there.