WASHINGTON — Some 2,000 members of Moms Demand Action, an antigun violence group formed after the school shooting in Newtown, Conn., were holding their annual conference here Saturday when news came that it had happened again.

Another mass shooting. This time in El Paso.

So instead of the typical dinner to mark the end of their gathering, the group’s members took to the streets. Chanting “Not One More!” they marched from the Capitol to the White House as the video streams they shot with their cellphones lit up the night.

“Because of the atmosphere, none of us felt we could celebrate,” said Kristi Cornett, who lost a family friend in a mass shooting in Aurora, Colo., and joined Moms Demand Action in her home of Nashville after the Pulse nightclub shooting in Orlando. “We didn’t know what it was going to turn into, but it felt like something special.”


Just hours after a march many described as a cathartic experience, they awoke to more soul-crushing news. A gunman in Dayton, Ohio, opened fire in a nightlife district, killing nine people. “Today I am very sad,” said Kristen Bauer, a Moms Demand Action volunteer in Arlington, Mass.

The twin tragedies — coming within a week of a third mass shooting at a festival in Northern California — managed to stun a nation that has almost become immune to the constant news of gun violence.

There were swift and bipartisan denunciations of the attacks. But gun-control advocates, congressional Democrats, and the party’s presidential candidates pushed for more. They called for Senate majority leader Mitch McConnell to take up bipartisan legislation tightening background checks that he has sat on since it passed the House last winter.

But even as law enforcement officials provided new details about the horrors in El Paso and Dayton this weekend, the reality quickly set in across a politically divided nation: Without similar calls from Republicans in Washington, which did not come on Sunday, there is unlikely to be any kind of legislative response, pushing the issue to the fore of the 2020 presidential campaign.


“We are at a tipping point in terms of public debate,” said Adam Winkler, a gun-policy expert and law professor at the University of California Los Angeles. “But Republicans still control the Senate, Trump still controls the White House. There is not going to be any significant change as long as those two things continue to exist.”

House Democrats have introduced dozens of proposals to address gun violence, including legislation to revive bans on assault weapons and large-capacity magazines that expired in 2004. They made major progress in March when they passed two bipartisan measures — long blocked when Republicans controlled the House — to strengthen and expand background checks. One would give federal law enforcement officials more time to complete the verification process, the other would require that it be applied to purchases beyond those at licensed dealers, including those at gun shows, online, and in other private settings.

But the measures have stalled under McConnell in the Senate, and his office would not comment Sunday on whether he would allow a vote.

McConnell tweeted Sunday morning that it was “sickening to learn this morning of another mass murder in Dayton, Ohio overnight” and that “We stand with law enforcement as they continue working to keep Americans safe and bring justice.”


David Popp, his communications director, on Sunday said only that McConnell had tripped that morning outside on his home patio and suffered a fractured shoulder. He was treated and was working from home in Louisville, where he contacted Republican Senators John Cornyn of Texas and Rob Portman of Ohio to express his sympathies and “discuss the senseless tragedies of this weekend,” Popp said in a statement.

The difference in approach to the mass shootings from Democratic and Republican lawmakers was further on display at a news conference in Dayton, where Senator Sherrod Brown, Portman’s Democratic colleague, described his emotions after the initial concerns for the victims and first responders.

“My next thought was anger at our country and society and our Congress for not doing anything about this,” he said, calling for McConnell to bring the Senate back into emergency session to approve the House background-check legislation this week.

“We certainly pray for the victims and care about the victims, but Congress needs to do something,” he said.

Speaking immediately after him, Portman said Congress could only do so much, pointing to suicide and drug-addiction rates as well as a mental health crisis.

“Are there more things that can be done? I’m sure there are, but I will say there’s something deeper going on here,” Portman said. “There aren’t enough laws, and in fact no law can correct some of the more fundamental cultural problems we face today as a country, and the shooting last night is an indication of that.”


President Trump echoed those thoughts in comments Sunday afternoon.

“If you look at both of these cases, this is mental illness,” Trump said as he boarded Air Force One in New Jersey Sunday to return to Washington, promising to deliver a more detailed statement on Monday. “These are really people that are very very seriously mentally ill.”

Gun policy experts called the deflection to mental illness and other potential causes, such as drug addiction, rock music, and video games, an old diversionary tactic.

“All of these things are relevant to discuss and look at, but none of these get to the root cause of what is causing this violence — which is easy access to firepower,” said Robert Spitzer, a political scientist at the State University of New York at Cortland. “You can’t commit a mass shooting if you can’t get guns.”

In the 2020 election campaign, young activists have already elevated the issue of gun control, even though it has not historically played well in the South and interior regions of the country, where Republicans and the National Rifle Association have stoked fears that the government could take away people’s guns. Polls show that an overwhelming and bipartisan majority of Americans support expanded background checks. A majority of Americans, mainly Democrats, support a ban on assault weapons.

Democratic presidential candidates on Sunday rushed to call for action on gun-control legislation and to condemn Trump’s rhetoric, which they blamed for inflaming the white nationalism that law enforcement officials believe spurred the attack at a Walmart in El Paso now under investigation as a case of domestic terrorism.


Democratic candidate Beto O’Rourke, who is from El Paso, said Sunday that he agreed with a description of Trump as a white nationalist.

“It is not just President Trump, but he’s certainly — as the person in the position of greatest public trust in power — most responsible for it,” O’Rourke said. “This is what we’re seeing on the Internet. This is the toleration of intolerance and hatred and racism in this country. This is what we’re seeing here today, and it will continue to happen unless we call it out and unless we change it.”

Jazmine Ulloa can be reached at jazmine.ulloa@globe.com. Follow her on Twitter @jazmineulloa

Correction: An earlier version of this story incorrectly said Kristen Bauer was from Arlington, Va., and not Arlington, Mass.