Lachlan Cartwright still feels guilty. The Australian remembers watching in horror as a fake story about a Trump rival planted by his employer, the National Enquirer, was picked up by the mainstream media and used as ammunition by Donald Trump in his campaign to win the presidential nomination for the 2016 election.

The article was based on a dubious photo suggesting Texas senator Ted Cruz’s father was with John F. Kennedy’s assassin shortly before he murdered the US president. It was an attempt by the top-selling magazine to sway the campaign in Trump’s favour.

But even before that article appeared, Cartwright, who is now a special correspondent for The Hollywood Reporter, could sense that something wasn’t right.

The Enquirer had already allegedly made a hush-money payment to silence a Trump Tower doorman who dubiously claimed that Trump had a love child.

And within months – as the election day race neared against Democrat Hillary Clinton – it would purchase another one, this time to bury an alleged affair with a Playboy playmate.

“By that point, I’m in the pub, saying to my mates: ‘Look, I think there’s something going on here’ because we were running all these crazy covers, claiming that Hillary only has six months to live or that Ted Cruz’s father is caught up in JFK’s assassination with Lee Harvey Oswald,” he tells this masthead.

“I just didn’t know the size and the consequence of what was happening until I read the charges against Trump last year – and that’s when everything fitted into place.”

Cartwright worked as an executive editor at the Enquirer alongside fellow Australian Dylan Howard. He is not a witness in Trump’s historic hush-money trial but can describe the stories published at the time under David Pecker, the publisher of the tabloid magazine, who this week testified how he became entangled in a high-stakes scheme to help Trump become president.

According to prosecutors, the alleged conspiracy began in August 2015, two months after Trump announced his bid for the White House.

Pecker gave evidence that during a 20-minute meeting convened by Trump’s personal lawyer, Michael Cohen, Pecker agreed to use his network, as the publisher of the top-selling National Enquirer, to be the “eyes and ears” of Trump’s 2016 election campaign: burying damaging stories about his alleged infidelities and running negative news about his political rivals.

After leaving Trump Tower in Manhattan that day, Pecker contacted Howard, his loyal lieutenant, to inform him of the “highly, highly confidential” plan.

“I told him we’re going to try to help the campaign, and to do that, I want to keep this as quiet as possible,” Pecker said, testifying as the first witness in Trump’s historic trial.

As the editor-in-chief of the Enquirer, Howard was no stranger to the dark art of tabloid chequebook journalism.

The 42-year-old had cut his teeth as a sports writer at the Geelong Advertiser, but rose to prominence as a reporter at Seven after a controversial story that involved publishing and paying for the private medical records of two AFL players that a member of the public had supposedly “found” in the gutter. He was cleared by a police investigation.

Later, he reinvented himself in the United States as a glittering gossip reporter and then as an editor with an unflinching knack for sourcing scandals involving the rich and famous.

Donald J. Trump, a former reality-TV star-turned-presidential candidate, was no exception.

During hours of explosive testimony on Wednesday (AEST), Pecker said he had no doubt there would be people seeking to exploit Trump as he ran for office because he had been “well known as the most eligible bachelor and dated the most beautiful women”.

As such, his message to Howard was simple: be on alert for anything that could derail the Republican candidate’s campaign. If someone came forward with information, “vet the stories and bring them to me”. Pecker gave evidence that he would then speak to Cohen, and they would move to bury the claims using hush money and non-disclosure agreements – a practice known as “catch and kill”.

It didn’t take long for the first potentially damning allegations to emerge. In October 2015, Howard received a tip from a doorman at Trump Tower named Dino Sajudin, who claimed that Trump had a love child with a woman who worked at his property.

Trump furiously denied the claim and even offered to have a DNA test to prove he was not the father.

It is alleged that Howard, meanwhile, assigned a team of reporters to verify the story, which turned out to be false, but Pecker feared it could still damage Trump if it ever saw the light of day. As such, a deal was negotiated to pay Sajudin $US30,000 ($46,000 at current rates) for his silence.

Asked by prosecutors if he had ever paid a source to kill a story about Donald Trump before then, Pecker replied: “No, I did not”.

“I made the decision to buy the story because of the potential embarrassment it would have to the campaign and Mr Trump,” he added.

But while Sajudin represented AMI’s first 2016 campaign catch-and-kill payment, it wouldn’t be the last.

Eight months later, it’s alleged that Howard received a call from California-based lawyer Keith Davidson, who told him about another “blockbuster” story. This one involved former Playboy playmate Karen McDougal, who claims she had a year-long affair with Trump.

After getting the tip, Pecker said he dispatched Howard to fly to Los Angeles to meet Davidson, and he ended up interviewing McDougal for “two or three hours to vet her story”. She was later given $US150,000 to ensure the story wouldn’t get out.

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Howard now lives in Australia, and the court was told he has a spinal injury that will prevent him from appearing as a witness in the trial. Asked if he’d care to make any comment, his lawyer, John Harris, told this masthead: “Dylan Howard has always fully co-operated with government inquiries regarding his former employer’s relationship with Donald Trump, and the actions he was directed to do.

“But for Mr Howard’s inability to travel, he would have again, voluntarily, answered questions at the trial.”

Trump faces 34 counts of falsifying business records relating to a third hush-money deal involving porn star Stormy Daniels, to whom Cohen allegedly paid $US130,000 to cover a tryst she claims she had with the former president.

Prosecutors allege that Trump reimbursed Cohen but fraudulently disguised the payment as a legal retainer, thereby violating election laws.

However, burying news of Trump’s alleged infidelity wasn’t the only part of the scheme, Pecker told the jury.

The other part involved publishing positive stories to boost the Republican’s popularity, while running negative stories about his rivals.

Pecker told the court that in some cases, he would tell Cohen about what they planned to publish and “send him the PDFs so he could see the direction they were going, and he would comment on them and add content”. Other times, “Michael Cohen would call me and say: we would like you to run an article”.

“The National Enquirer would embellish it from there,” he added.

One story alleged Republican primary candidate Ben Carson, a former surgeon, had botched an operation and left a sponge in a patient’s brain.

Another claimed that Marco Rubio, who was also running for the presidential nomination against Trump that year, had a “cocaine connection” and a “love child”.

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And Cruz, who was initially beating Trump in the Republican primaries, was also a major target.

“That’s the thing people need to understand: this case isn’t just about hush money. This case is fundamentally about election interference,” says Cartwright.

“It’s about a media organisation using the cover of the First Amendment to twist itself into a criminal enterprise to suppress negative information to get a person elected. That person is Donald Trump. And guess what? It worked.”

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