In this new role, as with so many of his roles for Trump over the years, Scavino continued to serve as a kind of caddy. He went on food runs for the candidate to McDonald’s and KFC. He faithfully typed out Trump’s tweets as the candidate dictated them. He also wandered the events, climbed the rafters and snapped smartphone pictures, which he then posted on both his and the campaign’s various social-media accounts. It happened that the campaign already had a professional photographer on the payroll. But this was becoming a liability, in that she tended to take hundreds of images at each event, and the candidate would insist on spending hours of valuable time poring over every last one of them. The campaign did nominally have a social media specialist — Justin McConney, son of the Trump Organization’s controller — but he lacked Scavino’s instinct for the base, and in any event, McConney was stationed back at Trump Tower, away from the real action on the campaign trail. By early 2016, Scavino had become in essence both the Trump campaign’s traveling photographer and its social media chieftain. And because the self-funding candidate had no intention of spending a dime on media coverage, Scavino with his Facebook videography also became the closest thing the Trump campaign had to an in-house ad maker.

Scavino’s willingness to take on other people’s online grunt work made him indispensable to the campaign. Early in the primary, the candidate’s son-in-law, Jared Kushner, argued to Trump that Facebook was much more powerful than his preferred platform, Twitter. “Every Facebook user is probably worth 10 to 12 times more than one of your Twitter followers,” Kushner told him. “And look, I think your Facebook page is totally underutilized.” The candidate responded, “Congratulations, then — you’re now in charge of my Facebook.” Kushner turned around and handed over that job to Scavino.

Even as Scavino’s deployment of campaign imagery onto Facebook helped accelerate the Trump Train, it was Twitter, with its visceral impact, that remained Trump’s abiding love. “Somebody said I’m the Ernest Hemingway of 140 characters,” he crowed during an event in South Carolina in November 2015. (The “somebody” was most likely one of his employees.) On his plane or in limousines, he would dictate tweets for Scavino to post. Others, including Scavino, would goad Trump with their own suggestions. (Hope Hicks would supply the choicest put-downs, recalls a former campaign official: “She’d have absolute daggers.”) Trump would give his missive a final read to make sure that it had not been watered down, and Scavino would hit “Tweet.”

Now and again, Trump would enlist Scavino — whose followers today exceed 475,000 — to act as a proxy, attacking the campaign’s enemies from his own account. At other times, Scavino took the initiative himself. Before long, the personal feed that had once been a totem of cornball folksiness included harsh attacks on Megyn Kelly, “Lyin’ Ted” Cruz and other perceived antagonists. In March 2016, Scavino retweeted a conspiracy video purporting to demonstrate that Cruz was having an affair with a former aide, Amanda Carpenter. Carpenter, who is married with children, went on the air and heatedly denied any impropriety. She also condemned Scavino by name, calling his attack a “smear job.”

“It was a campaign, and they fight dirty, and they didn’t mind if I was collateral damage in the process,” Carpenter told me. “And they won. And no consequences. What Scavino did to me and what he still does to others would get any other professional fired. In Trump’s universe, it’s a qualification. A willingness to engage in lies and smears on behalf of Donald Trump is a sign of loyalty that Trump treasures.”

“It’s so great that I have Twitter now, because I can knock the crap out of people,” Donald Trump told me one afternoon in late March 2016 at his South Florida country club Mar-a-Lago. “I have my own printing press now!” he added with Falstaffian relish.

Still, nothing in Trump’s earliest social media forays would prefigure the towering role that Twitter eventually played in his political branding. Trump opened his @realDonaldTrump account in March 2009, only to ignore it for the better part of two years. Giving in to the urging of his political advisers Roger Stone and Sam Nunberg, Trump began to tweet about his hotel properties and his TV show. Soon he offered up sundry nuggets on his importance to the Yankees (“They always win when I am there”) and on how to succeed in life (“Show me someone without an ego, and I’ll show you a loser”). Like a fading matinee idol, Trump had an embarrassing tendency to preen, particularly once his musings turned to politics, around the run-up to the 2012 election. “My daughter Ivanka thinks I should run for president,” he tweeted on Jan. 25 of that year. “Maybe I should listen.” (“He’d be phenomenal!” Ivanka exclaimed in the linked Hollywood Life article.)