Mourners visit the makeshift memorial near the Walmart in El Paso where 22 people were killed in a shooting that police are investigating as a terrorist attack targeting Latinos. (Cedar Attanasio/AP)

A bloody summer marked by four major mass shootings has exposed a new divide in the Democratic Party that can be seen in the divergent responses of two young Texans with a claim on the party’s future.

Presidential candidate Beto O’Rourke, the former congressman from El Paso, spent the final weeks of August demanding mandatory buybacks of millions of assault rifles currently owned by law-abiding Americans. “All of them,” he tweeted defiantly.

Rep. Colin Allred, a freshman from suburban Dallas who flipped a Republican-held seat in 2018, calls such a move a worrying break from tradition, even as he supports a number of other new gun regulations.

“I don’t think that in our country we’re ever going to really go around having any kind of mandatory program like that,” he said.

The split among Democrats between dramatic action and practical politics has added a complicated wrinkle to the gun debate now roiling Washington and the campaign trail.

Democrats in Congress have focused on putting pressure on Senate Republicans to pass popular measures, like expanded background checks, while exploring more modest efforts to allow law enforcement to remove guns from the mentally unstable. Both ideas are supported by more than 8 in 10 Americans, including self-identified Republicans.

At the same time, House Democrats have held off so far on scheduling a vote for a renewal of the 1994 assault weapons ban — blamed for helping to spark a pro-gun political backlash after its passage but now supported by 90 percent of the party’s members of Congress. They are choosing instead to advance a bill that would limit the sale of ammunition magazines that hold more than 10 bullets, which some lawmakers see as a more targeted way of removing the danger of mass shootings.

Rep. Mike Thompson (D-Calif.), who as chairman of the House Gun Violence Prevention Task Force is the foremost messenger on gun legislation for Speaker Nancy Pelosi (D-Calif.), brushed off questions Tuesday about a new ban on assault weapons.

“What we have to do at this point is get the Senate to take up and pass the background check bill,” he said. “That bill saves lives right away, and we don’t have to do any more than that at this time.”

Presidential candidates, meanwhile, have been rushing in the other direction, pushing beyond the promise President Barack Obama repeatedly made to not take away anyone’s legal guns. “Most gun owners know that the word ‘common sense’ isn’t a code word for ‘confiscation,’ ” Obama said in 2011.

All of the top candidates support the assault weapons ban, and several have proposed mandatory or voluntary gun buybacks, new licensing and insurance requirements for gun ownership, or even new taxes that would dramatically increase the costs of legal gun ownership.

In past cycles over the past two decades, Democratic presidential candidates have steered clear of such positions, boasting of their affinity for hunters and downplaying gun politics in campaigns. The opposite is true now. When a CNN reporter asked former vice president Joe Biden this summer whether people needed to worry that his administration would “come for my guns,” he did not hesitate.

“Bingo, you’re right, if you have an assault weapon,” said Biden, a centrist by the field’s standards. “The fact of the matter is, they should be illegal, period.”

His campaign later clarified that he supports only a voluntary gun buyback, not a mandatory confiscation program like that proposed by O’Rourke. South Bend, Ind., Mayor Pete Buttigieg, former housing secretary Julián Castro, Sen. Bernie Sanders (I-Vt.) and businessman Andrew Yang have also said they support voluntary buybacks. Sen. Kamala D. Harris (D-Calif.) told reporters in New Hampshire on Friday that mandatory buybacks were “a good idea.”

“There is just this sort of liberation among the candidates that I see,” said Rep. Eric Swalwell (D-Calif.), who mounted a brief presidential effort this year focused on a mandatory buyback platform. “They lead with their gun-safety proposals instead of waiting to be asked about it.”

Republican opponents have embraced these arguments as helpful in exciting their base because polls show a big partisan split on the issues of an assault weapons ban and gun buybacks. A Washington Post-ABC poll published this week found 74 percent of Democrats supported a mandatory gun buyback program for assault weapons, compared with 31 percent of Republicans. Support among all parties was higher for a ban on new assault weapons sales but well below the level among Democrats and Republicans alike for expanded background checks or letting police take guns from those judged dangerous.

“I spent August recess making fun of people who say ‘nobody wants to take your guns,’ ” said Rep. Thomas Massie (R-Ky.), chairman of the House Second Amendment Caucus. “Don’t tell me that — I serve with the people that want to take your guns. What they should say is: We want to take your guns, but we’re not sure politically we can achieve that and keep our majority, and we know the president won’t sign it, so we’re not gonna take your guns yet.”

The Trump campaign also has been eager to shift the debate away from background checks and mental health screenings to more fundamental efforts to deny law-abiding people their weapon of choice.

“Democrats have finally admitted what they truly want: a repeal of the Second Amendment,” said a recent Facebook ad paid for by the Trump campaign and the Republican National Committee. That is false: No Democratic candidate has proposed repealing the Constitution’s Second Amendment, which describes “the right of people to keep and bear arms” and has long been interpreted by courts to allow the regulation of gun sales.

Advocates for more gun regulation say the different approaches to the gun issue by members of Congress and presidential candidates stem from their different roles.

“The job of presidential candidates is to talk about the future, and the job of Congress is to focus on what they can pass now,” said John Feinblatt, the president of Everytown for Gun Safety, a group supporting more gun regulation backed by former New York mayor Michael Bloomberg. “The days when this was the third rail of American politics are over.”

The issue of mandatory gun buybacks has not been on the top of many gun regulation groups’ agendas, in part because there is not much research on its potential effectiveness compared with that of other approaches. But there has also not been much pushback, despite an acknowledgment that it is a less popular approach that will have a harder time passing Congress.

“I view what former congressman O’Rourke is proposing as something very visceral to his community,” said Robin Lloyd, the managing director of Giffords, a gun violence prevention group founded by former congresswoman Gabrielle Giffords (D-Ariz.). “It is really hard to know if this is something that the American people are going to want to do.”

Democrats representing more moderate districts have offered clear notes of caution, especially on the question of reinstating a ban on assault weapons. A bill to do this in the House has 211 co-sponsors, and members are hopeful that it will get a floor vote if they can reach 218.

But the original sponsor of that bill, Rep. David N. Cicilline (D-R.I.), said this week it made sense to focus on the background-checks bill, and he expressed qualms about expanding his own assault weapons bill to seize existing guns.

“I think if you add confiscation or mandatory buybacks, it would make it impossible to move the bill,” he said. “The reality is, every other bill that we’ve done tries to keep guns out of the hands of people who shouldn’t have them.”

Rep. Ron Kind (D-Wis.), a moderate representing a rural district, said there were still a lot of doubts in rural America about the 1994 assault weapons ban. Many gun owners saw the restrictions in the bill as arbitrary and unrelated to actual safety concerns.

“How do we define it in such a way where there are clear lines of legal authority so you’re not making criminals out of people who are confused about what the definition is?” he said. “I think that’s something that you have to certainly address and make sure that they tighten up if the experience with the assault weapon ban was any indication.”

Other liberal members of Congress willing to entertain mandatory buybacks have tried to modify Obama’s framing of the gun debate, which flatly ruled out gun confiscation.

Rep. Jamie B. Raskin (D-Md.) noted that the Supreme Court has affirmed the right to own handguns for self-defense or rifles for hunting and recreation but kept the door open to other gun regulations.

“Nobody’s taking away people’s basic guns that they can use for legitimate purposes in our society,” he said. “But what is happening is that we want to get rid of the weapons of war.”