Donald Trump sat in a New York courtroom Monday watching history unfold, a glum witness to his own turn as the first US president to face criminal prosecution.

Most court proceedings are deliberate, scripted and glacial — tedious for any observer to sit through, let alone a brash real estate mogul used to getting what he wants, when he wants.

But the 45th president vying for another go in the nation’s highest office is set to spend the next month or two forced to sit in a drafty 15th-floor courtroom with peeling paint and fluorescent lights, speaking only when spoken to.

In their opening statements, prosecutors detailed how Trump allegedly falsified business records as part of a scheme to pay off adult film actress Stormy Daniels in a bid to protect his 2016 presidential aspirations.

The former president slouched and stared straight ahead as Matthew Colangelo laid out details of Team Trump’s collusion with the boss of the media group specializing in celebrity tabloids, who prosecutors say worked with the Republican to conceal damaging stories.

Colangelo took care to smoothly quote the vulgar words that Trump uttered when caught on an infamous tape bragging about grabbing female genitalia without consent.

It was then that Trump flinched, shaking his head as he heard his own transcript read aloud to a packed courtroom, the audio amplified into an overflow room seating dozens more journalists.

But as his defense lawyer Todd Blanche delivered his opening statement, Trump turned toward the jurors, poised somewhere between intimidation and ingratiation.

‘Trying to influence an election’ is simply ‘democracy’ Blanche said, noting that the rich and famous routinely use non-disclosure agreements.

‘The 34 counts,’ Blanche said, referring to the business record falsification charges Trump faces, ‘are really just pieces of paper.’

Glares, and laughter

In contrast, first witness David Pecker brought a buoyant energy to the court.

Sporting a yellow tie, mustache, slicked-back hair and an ear-to-ear smile, he looked a stereotype of the tabloid man he is — a former executive whose outlets included The National Enquirer, which prosecutors say bought up and tried to squash salacious stories about Trump as he ran for president.

‘We used checkbook journalism,’ Pecker told jurors, explaining his company’s editorial practices.

Pecker even engaged in banter with prosecutors asking him to recount a series of phone numbers he had while heading American Media, at one point letting out an infectious cackle.

As a real estate scion making a name for himself in 1980s and 90s Manhattan, Trump relied heavily on tabloids to bolster his rise to fame — and the testimony threw into relief how gossip mags could now play a key role in his fate.

The former president glared at Pecker before court recessed early due to the Passover holiday, and because a juror had an emergency dental appointment.

Outside the court building, the frenzy is easy fodder for tour guides: one pointed out journalists nearby who were hunched over laptops, alternating between clacking out quotes and slurping down noodles.

The guide smiled as his group paused their bike ride to take in the spectacle: ‘Trump reporters,’ he said.