(CNN)It was just after lunchtime the day after Barack Obama won re-election, and Donald Trump was about to try out a new line on Twitter.
Twitter and Trump: Marriage of man, message and machine
He was hardly a novice on the microblogging site. Since @RealDonaldTrump announced itself to the world in 2009 with a plug to watch Trump read David Letterman's Top Ten List, he had sent thousands of tweets -- to promote his brands, roast celebrities and build a steady following with musings like "You never see a thin person drinking Diet Coke."
One constant among the 140-character bursts were hints of his political ambition.
"THe (sic) people at shouldtrumprun.com have got it right! How are our factories supposed to compete with China and other countries..." was one of the first tweets Trump sent with his own hands (and it failed to mention that shouldtrumprun.com was created by his own lawyer).
Peter Costanzo, a digital marketer with Trump's publishing company, ran his account for the first eight months, often posting aspirational quotes pulled from the billionaire's books. But when Trump took over, the feed became noticeably more aggressive.
In 2011, a few weeks after Barack Obama mocked him at the White House Correspondent's Dinner, Trump launched his very first Twitter attack on the sitting President. Over a thousand more would follow. He tweeted his "birther" conspiracy theory more than 60 times before admitting the truth, yet during the 2012 election, none of it seemed to matter. Obama beat Mitt Romney easily. Around 2 p.m. the next day Trump tweeted the line that would change history.
"We have to make America great again!"
Few noticed. Today the tweet has less than 1,500 likes. But it marks a seminal moment in the marriage of man, message and machine that defied the laws of political physics and helped to make Trump the most powerful person on earth.
With almost 36 million followers, @RealDonaldTrump is far from the most popular account on Twitter. Katy Perry, Justin Bieber and Barack Obama each have close to three times as many followers.
But each Trump tweet is news, rocketing from Washington to every corner of the planet at the speed of digital light.
"I'm going to do it very restrained, if I use it at all," Trump told "60 Minutes" after winning the White House. But it soon became obvious that his unfiltered thoughts and barbs would not let up once in office.
In the weeks after the election, his targets ranged from China to Joy Behar of "The View," adding to a Nixonian enemies list that the world could watch grow in real time.
Public Enemy No. 1, as far as Trump is concerned, is the mainstream media. He's made his distrust clear through constant criticism and aggressively taking on traditional print and broadcast outlets. Twitter soon became a conduit for the former "Apprentice" host to express his views without the interference of a TV screen or microphone.
Once in office, he continued to use Twitter as both a sword -- against political foes and the press -- and a shield -- against historically low poll numbers and the Russian collusion investigation. He's tweeted the words "witch hunt" 17 times since January. But announcing policy on Twitter has proven the most problematic.
By tweeting his defense of a travel ban from Muslim countries, he gave opponents legal ammunition to stop it in court. His proclamation on Twitter that transgender people could not serve in the military caught the Pentagon by surprise. His tweets also often reverse the careful messages of his own communications team.
"I think if Donald Trump implodes, it'll be because of Twitter," says presidential historian Douglas Brinkley. "He puts things on the record that he thinks are an emotion of the moment. But he's creating a legal record for himself. A reckless use of Twitter could cause him to go down in the end."
But his base of defenders love the raw, unfiltered access to their President. "Every time he tweets, I am entertained. Sometimes I'm informed. It tells me what to care about today, tells me what he's thinking," says Scott Adams, creator of the Dilbert comic strip and an early Trump supporter. "It's transparent. Sometimes it's provocative. Sometimes it's too provocative. I like that, too."
The presidents we remember took the existing communication tools of the day and made them their own. Teddy Roosevelt courted cartoonists in a whole new way, FDR spoke into a radio microphone like no leader before and, while Truman and Eisenhower were the first on TV, Kennedy and Reagan are considered the best.
Likewise, Obama may have been the first POTUS on Twitter, but Trump is leveraging it in ways that will be studied for centuries -- and despite calls from both critics and allies to give it up or tone it down, few believe he will.
"My use of social media is not Presidential - it's MODERN DAY PRESIDENTIAL," he tweeted in July. "Make America Great Again!"