President Trump celebrated his administration’s victories, lambasted political foes or anyone who crossed him, handed down policy edicts and steered the Washington debate through 2017 — and he did all on Twitter.
The presidential tweets began less than an hour after Mr. Trump took the oath of office on Jan. 20.
“Today we are not merely transferring power from one Administration to another, or from one party to another – but we are transferring … power from Washington, D.C. and giving it back to you, the American People. #InaugurationDay,” he wrote.
At the very least, his prolific tweeting — nearly 2,500 messages since taking office — changed the way journalists cover the White House and the way Americans experience their president. They caught glimpses of his thoughts in nearly real time as he remarked on virtually every twist and turn of his first year in office.
Emerson College communications professor David Gerzof Richard, who founded of the tech-savvy public relations firm BIGfish PR, said the billionaire businessman and former reality TV star brought a celebrity mindset to Oval Office tweets and made a clean break from his predecessors, who relied largely on the news media to deliver their messages to the world.
“Much like the celebrities and athletes who discovered Twitter before him, President Trump uses the platform to tell his story, his way,” said Mr. Richard. “There is no editorial board, no fact checkers, no advisers, no filters — just a direct conduit to tens of millions of followers.”
After his inauguration, Mr. Trump quickly showed a pattern of tweeting reactions to Washington news reports. His tweets then became the news.
“Watched protests yesterday but was under the impression that we just had an election!” Mr. Trump tweeted about the Women’s March on Washington the day after the inauguration. “Why didn’t these people vote? Celebs hurt cause badly.”
The celebs to which he referred included feminist icon Gloria Steinem, pop star Madonna and actress Scarlett Johansson, who joined the march to protest the new president.
The White House later acknowledged that Mr. Trump’s tweets were official statements.
The president’s tweets marked high points for his administration, such as congressional approval of the Tax Cuts and Jobs Act that is the cornerstone of Mr. Trump’s economic agenda.
“The Massive Tax Cuts, which the Fake News Media is desperate to write badly about so as to please their Democrat bosses, will soon be kicking in and will speak for themselves. Companies are already making big payments to workers. Dems want to raise taxes, hate these big Cuts!” he declared.
He commended the military for executing missile strikes he ordered in April against a Syrian airfield after the brutal regime used chemical weapons against civilians.
“Congratulations to our great military men and women for representing the United States, and the world, so well in the Syria attack,” he wrote.
Mr. Trump also vented during low points.
When National Security Adviser Michael Flynn was forced to resign in February after lying about contacts with Russian officials during the presidential transition, Mr. Trump attempted to set the record straight via Twitter.
“The real story here is why are there so many illegal leaks coming out of Washington? Will these leaks be happening as I deal on N.Korea etc?” he tweeted.
The Russia investigation that cost Mr. Flynn his job and dogged Mr. Trump since his election often fueled his twitter tirades.
“After 7 months of investigations & committee hearings about my ‘collusion with the Russians,’ nobody has been able to show any proof. Sad!” he wrote in June.
He unleashed a torrent of tweets in October when special counsel Robert Mueller’s Russia investigation filed its first charges: a 12-count indictment against former Trump campaign chairman Paul Manafort and his business partner Rick Gates that included money laundering and making false statements.
“The Dems are using this terrible (and bad for our country) Witch Hunt for evil politics, but the R’s are now fighting back like never before. There is so much GUILT by Democrats/Clinton, and now the facts are pouring out. DO SOMETHING!” he said.
Mr. Trump’s posts were often aimed at settling scores.
“He uses Twitter like a Death Star laser,” said Mr. Richard. “If he doesn’t like the position of a politician, reporter or some other person, look out. Trump can direct his tweets and, through them, his Twitter followers at a specific individual, thus focusing millions of people on that one person at one time.”
He said Mr. Trump’s mean tweets were “like a kid directing the sun through a magnifying glass onto an ant.”
When Senate Foreign Relations Committee Chairman Bob Corker criticized the president’s foreign policy skills, Mr. Trump called the Tennessee Republican a “lightweight” and “incompetent.”
When Sen. Kirsten E. Gillibrand, New York Democrat, called for the president to resign over accusations of sexual harassment, Mr. Trump gave her the “lightweight” label on Twitter.
His comment that she was one of those politicians who would “do anything” for a campaign contribution caused a stir in the press corps, but White House press secretary Sarah Huckabee Sanders insisted that only reporters with “minds in the gutter” would read anything sexual into Mr. Trump’s remark.
In May, the president egged on the backlash against comedian Kathy Griffin for circulating a photograph of herself holding a mock-up of Mr. Trump’s severed head. The stunt effectively ended her career in the U.S.
“Kathy Griffin should be ashamed of herself. My children, especially my 11 year old son, Barron, are having a hard time with this. Sick!” he tweeted.
He took swipes at MSNBC hosts Mika Brzezinski and Joe Scarborough, calling them “low I.Q. Crazy Mika” and “Psycho Joe” and mocking Ms. Brzezinski with what he said was a face-lift.
Some of the president’s most belittling name-calling was reserved for North Korean dictator Kim Jong-un, whom he dubbed “little rocket man.”
At last count, Mr. Trump had 45.1 million followers on Twitter.
Former President Barack Obama has 98.3 million followers, but Mr. Trump outpaces his predecessor with the volume of tweets — more than 36,000 to Mr. Obama’s 15,500.
Since taking office, Mr. Trump had fired off 2,489 tweets as of Tuesday, including retweets and deleted posts, according to a tally by The Washington Times.
He used the term “fake news” in 140 tweets, mentioned his nemesis CNN on 40 occasions and 11 times exclaimed, “Sad!”
He used his campaign slogan, “Make America Great Again,” or MAGA in 98 tweets since becoming president.
Mr. Trump took the unprecedented step of using Twitter to announce major policy decisions. That didn’t always go smoothly.
The announcement on Twitter in July that he was barring transgender people from serving in the military “in any capacity,” reversing an Obama-era policy, proved to be premature.
Mr. Trump later formally directed the Pentagon to extend indefinitely a ban on transgender individuals joining the military, and he gave Defense Secretary James Mattis six months to come up with a policy on how to deal with those currently serving.
But federal courts stepped in to block the ban on transgender troops.
Mr. Trump’s tweets also muddied the waters for other policies. A series of federal judges cited his tweets in their decisions to strike down the administration’s travel ban that targeted seven predominately Muslim countries.
The judges said Mr. Trump’s tweets illustrated his anti-Muslim sentiments and the biased nature of the travel ban.
“The travel ban into the United States should be far larger, tougher and more specific-but stupidly, that would not be politically correct!” the president tweeted in September.
The Supreme Court eventually allowed the extreme vetting program to proceed after the administration rewrote the policy three times.
Mr. Trump even used Twitter to criticize his administration’s rewrite of the policy.
Twitter caused other problems for the president.
The White House scrambled to defend the president after he retweeted three videos in November showing violent beatings perpetrated by Muslims. One of the videos, which showed a purported Muslim immigrant in the Netherlands beating up a young man on crutches, had been discredited by Dutch authorities.
“Whether it’s a real video, the threat is real,” said Mrs. Sanders.
Mr. Trump also was criticized for potentially prejudicing legal proceeding by commenting on them, such as declaring the man accused in the deadly Halloween pickup-truck rampage on a Manhattan bike path “SHOULD GET DEATH PENALTY!”
Mr. Obama this week took a veiled swipe at Mr. Trump’s use of Twitter, warning that leaders should use social media responsibly.
“All of us in leadership have to find ways in which we can re-create a common space on the internet,” he aid in a BBC interview. “One of the dangers of the internet is that people can have entirely different realities. They can be cocooned in information that reinforces their current biases.”
Mr. Obama was the first president to use social media but used it far less than Mr. Trump.
• Dave Boyer contributed to this article.