Even some Republicans can still see that Trump is a bully. His personal attack on a working class guy in “flyover country” has not met with universal approval.

The Twitter message from the president-elect at 7:41 Wednesday night, and a second one urging Mr. Jones to “spend more time working — less time talking,” continued Mr. Trump’s pattern of digital assaults, most of them aimed at his political rivals, reporters, Hollywood celebrities or female accusers. On Tuesday morning, Mr. Trump used Twitter to assail Boeing for escalating costs on the development of a new Air Force One.

But rarely has Mr. Trump used Twitter to express his ire at people like Mr. Jones, the president of United Steelworkers Local 1999, who described himself on Thursday as “just a regular working guy.” With the full power of the presidency just weeks away, Mr. Trump’s decision to single out Mr. Jones for ridicule has drawn condemnation from historians and White House veterans.

The reasons are obvious. Trump’s attack was about as clear a case of bullying as one could up with, unless he had actually punched a small child in the face. Heads of state really aren’t supposed to use the bully pulpit as a literal bully’s pulpit. They aren’t supposed to go after ordinary citizens for public entertainment. It’s probably not a written rule, but that’s because heads of state are assumed to be responsible adults, not reckless aggressive bullies.

“When you attack a man for living an ordinary life in an ordinary job, it is bullying,” said Nicolle Wallace, who was communications director for President George W. Bush and a top strategist to other Republicans. “It is cyberbullying. This is a strategy to bully somebody who dissents. That’s what is dark and disturbing.”

Robert Dallek, a presidential historian, called the verbal attack unprecedented and added: “It’s beneath the dignity of the office. He doesn’t seem to understand that.”

No, he doesn’t. I think he thinks he brings added dignity to the office. I think he equates dignity with thick gold ornamentation, rather than with behaving like a decent human being who understands that other people have rights.

Frank Sesno, a former CNN Washington bureau chief and now the director of the School of Media and Public Affairs at George Washington University, said Mr. Trump’s willingness to weaponize his Twitter feed, especially against people who are not political rivals, could produce a chilling effect on people willing to publicly criticize the president.

“Anybody who goes on air or goes public and calls out the president has to then live in fear that he is going to seek retribution in the public sphere,” Mr. Sesno said. “That could discourage people from speaking out.”

Or it could encourage us to speak out all the more.

Mr. Trump’s message to his 17 million Twitter followers set off threats and other harassing calls to Mr. Jones. One caller left five one-minute messages, and two secretaries answering phones at the local’s headquarters have been similarly swamped.

“It’s riled the people up,” Mr. Jones said. “A lot of the people who have called and been not very nice to me, they have been quite clear that they are Trump supporters and I’m an ungrateful so-and-so.”

Trump ran on a bullying platform. That’s what drew a lot of people to him, that was the chief reason to vote for him for a lot of people. That’s why the rest of us are feeling so alienated and sick. We don’t want to live in Bully World.

Veterans of the White House say they do not know what to expect from Mr. Trump, whose actions since the election have broken with many presidential norms.

David Axelrod, who was a senior adviser to President Obama, said he always advised the current occupant of the Oval Office to be mindful of the extra power that his words carried once they were amplified by the most powerful megaphone in the world.

“What you may think is a light tap is a howitzer,” Mr. Axelrod said. “When you have the man in the most powerful office, for whom there is no target too small, that is a chilling prospect. He has the ability to destroy people in 140 characters.”

And he has zero ability to see why he shouldn’t do that. Zero.

Whether Mr. Trump will continue to use Twitter as president is unclear, though few people inside or outside Mr. Trump’s orbit believe he will give up his digital connection to millions of followers. Two spokesmen for Mr. Trump did not respond to emails seeking comment on his Twitter message about Mr. Jones.

If he continues to tweet, Mr. Trump may discover that his words carry new weight and are given new meaning when they come from the White House. Ms. Wallace said he may end up having meetings with world leaders that do not go well, and be tempted to tweet his disapproval.

“It’s irrevocable what you put out in a tweet. It’s not like you can take it back,” Ms. Wallace said. But she added that she does not expect Mr. Trump to change his behavior once he is inaugurated.

“There can be a transformation when you get into the office, but it’s usually on policy, not behavior,” she said. “I’m not sure that the office will change his nature.”