As President Trump addressed the nation after a weekend of mass shootings, Rep. Tim Ryan (D-Ohio) was watching.

Reading from a teleprompter, Trump condemned the “barbaric slaughters” but did not blame lax gun laws for the 31 deaths in El Paso and Dayton. In his closing, Trump asked God to “bless the memory of those who perished in Toledo,” naming the wrong Ohio city.

Shortly thereafter, Ryan, who rushed to Dayton after the tragedy, took to Twitter. “Toledo. Fck me,” he wrote.

Ryan is the latest Democratic presidential candidate to unleash his anger and frustration with raw, emotional language that would have been considered taboo in a pre-Trump era.

Ryan spokesman Michael Zetts said the tweet was the congressman’s spontaneous response to the president’s flub. The day before, Ryan expressed frustration on MSNBC with years of inaction on gun control policy by saying Republicans “need to get their s--- together and stop pandering to the NRA.”

“It affected him, being at the vigil with the community,” Zetts said. “I think those emotions just kind of came through, and those frustrations came through. And there’s no action [in Congress]. Years go by with just nothing.”

Democratic presidential candidate and Ohio congressman Tim Ryan visits the Oregon District in Dayton where a gunman killed nine. (Scott Olson/Getty Images)

Former congressman Beto O’Rourke, an El Paso native, also left the campaign trail abruptly this weekend after a gunman opened fire Saturday morning at a Walmart in the city, killing at least 22 and injuring dozens of others. A manifesto authorities are investigating for ties to the suspected shooter said the violence was motivated by fears of a “Hispanic invasion.”

For weeks, O’Rourke has been calling out Trump’s rhetoric on the campaign trail as racist. When a reporter asked O’Rourke on Saturday whether there was anything Trump could do to make things better, he let loose.

“Uh, what do you think? You know the s--- he’s been saying. He’s been calling Mexican immigrants rapists and criminals,” O’Rourke said, at times throwing his hands up and stammering in exasperation. “I don’t know. Like, members of the press: What the f---? Hold on a second!”

“It’s these questions that you know the answers to. I mean, connect the dots about what he’s been doing in this country,” O’Rourke continued. “He’s not tolerating racism. He’s promoting racism. He’s not tolerating violence. He’s inciting racism and violence in this country. So, you know, I just — I don’t know what kind of question that is.”

The willingness of candidates to cross this line is a sign of the times, said Vanessa Beasley, a communications professor at Vanderbilt University who studies presidential rhetoric.

“The norms for presidential decorum are in flux right now,” Beasley said. Usually, candidates are mindful of the importance of “acting presidential,” she said — which in the past meant staying calm.

In the past, there were penalties for losing your cool. A scream essentially ended Howard Dean’s campaign in 2004. During the 2000 campaign, George W. Bush described a New York Times reporter as a “major league a--hole” on a live microphone, causing a minor furor and a subsequent statement of regret.

But Trump’s behavior since taking office — the round-the-clock tweets, the inflammatory rallies, the profane tirades about everything from the Mueller report to foreign countries — has scrambled politicians’ understanding of how a candidate should act.

“I think the question becomes: What does looking presidential look like?” Beasley said, pointing to a division among the Democratic field between those like former vice president Joe Biden, who has promised a return to normalcy, and others who insist there is no “normal” after a Trump administration.

There’s another factor, too. Candidates’ language, Beasley said, may reflect the genuine fear and anger they — and voters — are feeling.

“When I watched Beto last night on television, he was [responding] as a community member. . . . If he hadn’t reacted that way, it would have been weird,” Beasley said. “The moment to show that there is something that makes you kind of lose your mind and not be calm is now, both in a strategic sense and an affect sense.

“It’s not about data. It’s about that feeling,” she added.

Other Democratic candidates are also pushing rhetorical boundaries. Sen. Cory Booker (D-N.J.), who in his campaign appearances emphasizes love and unity, didn’t mince words during Trump’s speech Monday.

In a private text message his campaign manager shared on Twitter, Booker wrote: “Listening to the president. Such a bulls--- soup of ineffective words. This is so weak. We should quickly condemn his lack of a real plan.”

Though Booker did not share the message himself, it’s hard to imagine his campaign manager tweeted it without the candidate’s permission.

But Beasley cautioned that the standards are gendered: While a male candidate using profanity can be viewed as relating to “how people in America really talk,” female candidates, because of sexist stereotypes, might be seen as showing “too much emotion” if they curse.

For instance, Sen. Bernie Sanders (I-Vt.) on the debate stage last week shouted, “I wrote the damn bill!” in response to a question about Medicare-for-all; he’s now selling merchandise with the phrase on it.

By contrast, the female candidates have all largely avoided swearing on the campaign trail so far, even though Sen. Kirsten Gillibrand (D-N.Y.) in past years has been known to invoke an f-word or two when discussing Trump.

Sen. Kamala D. Harris has been loath to even quote the president when it comes to his remarks on “shithole countries,” instead saying “S-hole countries” on the campaign trail. On Monday, she stopped short of saying “bulls---.”

“You can hear the frustration in my voice because here’s the thing: I’m sick of all the grand gestures,” Harris said in a phone interview with MSNBC about stalled gun-control legislation. “All kinds of grand gestures. All kinds of proclamations about B.S.”

Harris then immediately apologized for saying “B.S.” on air.

“The very same thing that people will praise men for doing as a form of leadership — like direct speech — for women it’s seen as … well, you know, it rhymes with rich,” Beasley said, herself sidestepping a curse word in an interview. “These communication patterns create another barrier for women, and that seems unfair.”

Meanwhile, O’Rourke, who went viral for his unfettered thoughts in El Paso, took to Twitter later to defend his response, profanity and all.

“I stand by what I said,” he tweeted.

Chelsea Janes contributed to this report.