The Washington Monument and President Trump are silhouetted on a snowy Monday as the president stops to talk to reporters at the White House. (Jabin Botsford/The Washington Post)

Sen. Elizabeth Warren, once one of President Trump’s biggest antagonists on Twitter, isn’t engaging the president these days — even after he went after the Massachusetts Democrat, her husband, and her beer. Trump didn’t come up in the Golden Globe Awards this year, a departure from the past two years where he was maligned repeatedly from the stage. A satirical cable show about him has been canceled. A group of rank-and-file House Democrats turned down Trump’s invitation to have lunch at the White House on Tuesday.

Trump, who recently pined about being lonely in the White House, is lately finding himself in a position he’s rarely been in over the past few years: Ignored.

His political cachet has been driven by an unerring ability to goad other people into fights that benefit him. The metric he cares about is owning the television ratings and national attention, more than polling or anything else.

So what happens when, instead, he is met with something of a shrug?

The new silent treatment limits Trump’s ability to dictate national coverage and frame the day’s debate. And it’s providing an early template for how Democratic presidential candidates may attempt to deal with him in 2020, essentially forcing him out of a conversation they want to have with voters.

Former secretary of housing and urban development Julián Castro, who announced his 2020 campaign over the weekend, mentioned Trump only in passing. Sen. Kamala D. Harris of California, during a book tour that served as a warm-up for a likely presidential campaign, rarely brought up Trump unless asked.

“My focus, if I were going to run,” Harris said recently on MSNBC, “it would not be Donald Trump.”

Trump has spent much of his presidency as an inescapable presence. On TV. On front pages. He is tucked inside commentary about football games and Grammy Award winners, and a presence during bus stop conversations and church potluck dinners.

“Donald Trump’s main activity, from the time when he joined his father’s company as a young man until he became president, was attention-seeking,” said Michael D’Antonio, a Trump biographer and author of the book “The Truth About Trump.” “It was as if he didn’t exist if he wasn’t being noticed. Irrelevance is, I think, more painful to him than failure.”

He has bedeviled his opponents with cutting nicknames and long prompted knee-jerk reactions among Democrats who have struggled with how to balance their outrage over him with their attempts to offer an alternative.

“In 2016 the theory was that . . . it was okay to be fixated on Trump because what he was saying was so inherently disqualifying that there was a path to victory in just reminding people how offensive he was,” said Brian Fallon, a Democratic consultant who was the spokesman for the Hillary Clinton campaign. “Obviously, that didn’t work out.”

As president, Trump will never be fully irrelevant. Yet rather than directly confront him, Democratic candidates in 2018 began trying something new: They stopped talking about Trump so much. They found that the more they spoke about him, the more it turned off disengaged voters. They could more easily win over moderate Republicans in swing districts if they avoided focusing on him, and Democrats didn’t really need to be reminded why they were angry at him.

Only 11 percent of the Democratic ads during the final month of the November elections mentioned Trump, according to data collected by the nonpartisan Kantar Media/CMAG and cited by USA Today.

“Simply being anti-Trump isn’t enough to win the Democratic nomination and won’t be enough to win” in 2020, said Guy Cecil, chairman of Democratic super PAC Priorities USA Action. “Democrats need to tell their own story and share a forward-looking vision for where they want to take the country.”

The most aggressively anti-Trump candidates — lawyer Michael Avenatti and activist Tom Steyer, who is spending millions to advocate for Trump’s impeachment — have decided against running for the Democratic nomination. Other candidates or would-be candidates have mentioned Trump only briefly before moving on to other topics.

“I am not afraid of him and I’m not afraid of his nasty language and his name-calling,” Sen. Kirsten Gillibrand (D-N.Y.) said in a video accompanying the Tuesday announcement of her presidential candidacy. “What this president is doing is inhumane and immoral.” She then went on to highlight her record in the Senate and her efforts to promote women’s rights and protect 9/11 first responders.

Warren embodies one of the most radical shifts in focus. She once sought to engage Trump frequently, squabbling with him on Twitter and emphasizing her willingness to scrap with him as one of her core strengths.

As she began her campaign this month — and tried to retell her life story — she has eliminated Trump from her lexicon almost entirely. She recorded a video of herself in her kitchen, drinking a beer and offering one to her husband (who declined). Trump criticized her, but she mentioned him only once during her later multiday trip to Iowa.

“I think we need to talk about our affirmative vision,” she told reporters in New Hampshire last weekend, when asked why she wasn’t bringing up her onetime chief nemesis. “I’m willing to fight — everyone knows that. . . . I talked serious policy here in New Hampshire and that’s what I’m going to keep on doing.”

Those challenges will get harder, particularly as Democrats move toward the general election.

“Democrats should not overlearn the lessons of 2018,” said Geoff Garin, a Democratic pollster, who argued that some level of combat with Trump will be necessary. “The midterms were about defeating Republican candidates for Congress, and 2020 will be about defeating Trump himself.”

One challenge for Democrats is to demonstrate they can capture the public’s imagination without invoking Trump.

“I do think a factor people will look at is, who . . . can cultivate a media ecosystem separate from Trump?” Fallon said. “Who has the ability to command media attention other than just lobbing attacks against Trump? Who is inherently interesting and compelling? Can Trump lob attacks at them without them getting caught in quicksand because of it? Because that is a good indicator for who can withstand the [chaos] that will be the 2020 general election.”

Linda Sarsour, a co-founder of the Women’s March, said that this weekend’s event would unveil a policy-heavy “Women’s Agenda” to emphasize what the Democratic House could focus on in 2019, and what presidential candidates could be discussing in 2020. While Trump was a huge focus in earlier marches, she said, the president’s daily outrage became a smaller and smaller part of the discussion.

“I don’t even pay attention to the president anymore; I focus on what needs to be done,” Sarsour said. “I don’t go down the rabbit hole of distraction; I don’t care whether he ordered hamburgers for people in the White House. I do follow the executive orders, because I want to know what we’ll be suing him over.”

Anthony Atamanuik, a comedian who became known primarily for his impersonation of Trump, saw his Comedy Central show canceled after the last of its 23 episodes aired in October.

The decision stemmed, he said, from a combination of the network’s skittishness over overtly political programming and Trump fatigue among viewers. Comedians have also struggled to strike the right balance with Trump, both in how to satirize events that are close to satirical on their own and how to find something new to say.

“I think there is a general fear that making fun of him gives him oxygen,” he said. “He says the same things; I could say verbatim what he’s said for two or three years. At a certain point we run out of commentary.”

David Weigel contributed to this report.