A little-known community thrives in the shadow of the president’s tweets, shouting back to each one. (Washington Post illustration; Jabin Botsford/The Washington Post)

It was a few minutes before 11 p.m. in Washington last Tuesday, and President Trump had a thought to share.

“FBI Director Comey was the best thing that ever happened to Hillary Clinton in that he gave her a free pass for many bad deeds!” he tweeted to his 28 million followers.

A determined few of them — the regulars — were waiting.

“He’s investigating you right now,” Jordan Uhl, a young executive at a start-up in the District, tweeted back to the president. “Do you realize that?”

“Says a lot that the sitting president is STILL crying about an election THAT HE WON,” freelance writer Mike P. Williams typed from London. “There’s something wrong with you; your skin’s so thin.”

And in Los Angeles, tech entrepreneur William LeGate scoffed: “Comey is the reason you got elected . . . even you & your supporters know that.”

Trump has transformed the nation’s highest office through his bombastic Twitter habits. Even people who don’t follow him may be showered by the retweets of his 140-character thoughts or the news coverage they generate.

Most Twitter users, though, don’t bother to click on Trump’s individual tweets to see the thousands of replies each receives. If they did, they’d discover a little-known community: LeGate, Williams, Uhl and scores of other recurring names — the folks who’ve made a devout habit of talking back to the commander in chief on Twitter.

“I have a notification set up so that when Trump tweets, the lights on my phone flicker,” Le­Gate says. “I try to respond right away.”

It might sound like an absurd, self-indulgent or exhausting hobby. To Trump’s most dedicated Twitter rebutters, it feels more like a responsibility.

I was waking up at 4 a.m. to catch his early morning rants,” says Kristina Wong, a comedian and performance artist in Los Angeles. “The mania of trying to keep up with this s--- is insane, but it was the only thing that gave me a sense of agency.”

Wong sighs. She knows how futile this sounds. If Trump even bothers to read his detractors’ tweets, he never responds to them. “But we have a Twitter president,” she says. “This is not a guy who will respond to petitions or reason. I think it’s important to continually hold him accountable, in a medium that everyone sees.”

Many of Trump’s most relentless Twitter correspondents share a similar origin story: Horrified by his election victory, they started following him on Twitter with mounting distress. Then there came a single tweet they just couldn’t let pass, and they responded — with a rant not to their own followers but directly addressed to @realDonaldTrump himself.

Most assumed it would be a cathartic howl into the digital abyss. Instead, thousands howled back.

In one of his earliest tweets to Trump, technology executive Rob Szczerba chided him for calling journalists the “enemy of the American people” and posted a photo montage of reporters who had been killed on the job. More than 10,000 Twitter users marked it as a “favorite” tweet, and hundreds weighed in with their own comments.

“I knew [Twitter] was a mechanism for the president to get a message out very quickly,” Szczerba says, “but I realized it was also a way for average people to be able to put their opinion out there, too.”

Talking back to the president might have seemed rude to an older generation. Twitter, though, is a medium that not only allows it but seems to invite it.

Franklin D. Roosevelt was among the first presidents to seek a more direct communion with the people, promoting his agenda via a radio series of “fireside chats.” Ronald Reagan made such addresses a weekly practice. Since then, presidents have scrambled to chase viewers and voters across an increasingly fragmented media landscape, which is how Barack Obama came to grant interviews to Ellen DeGeneres and Leonardo DiCaprio.

Obama was also the first president with an official Twitter presence. His polished account left the impression that every tweet had been cleared (if not written) by his aides. Trump, though, came to social media as a flamboyant, self-promoting reality-TV star — which morphed into a Twitter voice more raw and combative than any national politician in memory, given to frequent falsehoods and occasional misspellings.

Now he is president — and still tweeting. And the freewheeling conversation is going both ways.

When Trump crowed about a visibly awkward meeting with German Chancellor Angela Merkel (“Despite what you have heard from the FAKE NEWS, I had a GREAT meeting”), Bess Kalb replied: “Honey, you wouldn’t shake an ally’s hand.” Her tweet drew more than 2,000 “likes.”

And when Trump thanked fans at his rallies (“Amazing support. We will all MAKE AMERICA GREAT AGAIN!”), LeGate responded with a poll: “Trump voters, has Donald Trump failed to live up to your expectations?” More than 19,000 people responded, and 72 percent voted “Yes.”

The rebutters who dominate Trump’s replies tend not to be professional pundits: Kalb is a writer for “Jimmy Kimmel Live,” LeGate a computer-programming prodigy who founded a ­photo-sharing app. Many say they had never shared their political opinions publicly before this election. And while Trump certainly gets lobbed his share of vulgar and hateful messages on social media, his most prominent Twitter rebutters generally show more restraint.

Granted, some lose their cool now and then: Tony Posnanski tweeted that Trump looked “intimidated” and “weak” after his meeting with Merkel; LeGate once called him a “man-child . . . who has daily temper tantrums.” Wong has deployed graphic memes inspired by the lurid dossier on Trump compiled by a British spy. But a general code of conduct seems to prevail.

“I think it’s important to respond with facts, as if you were in a normal debate,” says AJ Joshi, an entrepreneur.

“The last thing that we need is to alienate the people who voted for Trump,” LeGate says, “because they’re Americans just like everyone else.”

Perhaps good behavior is rewarded? The folks highlighted in this story are hardly the most famous of Trump’s detractors, and they’re not always the speediest to respond to him. But thanks to the quirks of Twitter’s mysterious algorithms, their tweets keep rising to the top of Trump’s Twitter replies.

Why, exactly, is unclear. Twitter would say only that its mysterious algorithms prioritize “the best content first,” whatever that means. It certainly helps that all of them are “verified,” a mark of authenticity granted to accounts of particular public interest. And as their tweets are increasingly liked and shared, they’re often boosted higher still.

Along the way, many have become allies, or even friends, corresponding in group chats and retweeting one another.

In March, Uhl left his PR job to launch a website, the Opposition, that aims to be a go-to source for everything anti-Trump. He also joined up with Justin Hendrix, another Trump rebutter he met on Twitter, to organize (along with writer Andrea Chalupa) the June 3 multi-city “March for Truth,” demanding an impartial investigation of Trump ties to Russia. Wong, meanwhile, was invited to speak at a Tax Day protest in Los Angeles because of her tweets, and she met some of her online fans in person.

Social media can all too easily function as an echo chamber; Wong and her compatriots tend to be followed on Twitter by like-minded, left-leaning people. But a funny thing happened when these particular Trump critics started replying directly to their new president: Their words were seen by different kinds of people. And different kinds of people talked back to them.

“It’s like entering a very crowded bar and yelling into the crowd,” says German writer Christoph Rehage, “instead of staying outside and mumbling to yourself.”

Sometimes yelling is all that ensues. Other encounters have ended in harassment or even death threats. But “every so often,” Szczerba says, “you see people learning things that they hadn’t heard before.”

“If someone comes into a thread and says, ‘Isn’t it true that Hillary sold uranium to Russia,’ I feel the odd compulsion to say, ‘Well, no, I’ve dug into this once, and here are some trustworthy documents explaining why that’s not the case,’ ” says a California-based Trump correspondent who asked that his name not be used, because he’s concerned about politics affecting his professional work. “Sometimes people will say something like, ‘This probably won’t change my mind, but I’ll read it.’”

He added, “If I write a clear, true thing in this place, and somewhere between 100,000 and a million people see it” — as Twitter’s analytics indicated for one of his tweets — “then maybe I can persuade someone.”

But does Trump actually see the messages they send?

Rehage spent months convinced that his snark blew right past the president. “He would be a guy to just mute people he doesn’t like and scroll past,” he said in March.

Weeks later, though, he suddenly discovered his account had been blocked from interacting with Trump’s tweets. His days as a Trump Twitter rebutter were over.

“It was one of the most awesome things ever,” Rehage says now. “It means he really looks at the comments.”