DES MOINES — A week after shootings in El Paso and Dayton left 31 dead, Democratic presidential candidates came together to argue, sometimes emotionally, for stronger gun control.

At a forum organized by Moms Demand Action, Students Demand Action and Everytown for Gun Safety, the candidates spoke largely in one voice, condemning President Trump’s rhetoric and Republican intransigence on the issue.

“We have historic unity in the Democratic Party on guns,” Everytown founder and former New York mayor Michael Bloomberg said. “But we’re only halfway there. In the Republican Party, we still have a lot of work to do.”

Though El Paso native and former Rep. Beto O’Rourke missed the forum and the Iowa State Fair to attend victim funerals, he echoed those themes in a video message.

2020 Democratic presidential candidates on Aug. 11 escalated their criticism of President Trump, saying his rhetoric is stoking racism. (The Washington Post)

“We need to acknowledge that this is not an act of God, nor is it a force of nature, nor is it a natural disaster,” O’Rourke said, in a clip recorded at his home. “This is a human-caused problem with a human solution.”

That means “standing up to the racism and hatred and intolerance espoused by far too many in this country, including by the person who sits in the highest position of public trust in this land,” O’Rourke said.

Sen. Kamala D. Harris (D.-Calif.) also suggested that Trump’s rhetoric has created an environment ripe for hate crimes and violence, saying that while the president “didn’t pull the trigger,” he’s “certainly tweeting out the ammunition.”

Others focused on how to push a gridlocked Congress to act.

Sen. Elizabeth Warren (D-Mass.) outlined the gun control plan she rolled out for the occasion. Her goal, she said, is to reduce lethal gun violence in the country by 80 percent, a massive reduction that would be difficult to accomplish purely via federal action but a more specific target than ones outlined by many of her opponents.

Warren’s plan, released Saturday, echoed some ideas shared earlier by Sen. Cory Booker (D-N.J.) and Harris. Like Booker, she proposed a federal gun registry, background checks for all gun purchases, and a ban on assault weapons, high-capacity magazines and accessories such as silencers.

Like Harris, Warren said she would move gun control policies forward via executive action. Harris has promised executive action implementing broader background check requirements. She also said she would direct the Bureau of Alcohol, Tobacco, Firearms and Explosives to seize the licenses of gun dealers who violate the law and ban the importation of assault weapons.

Warren’s plan would increase the tax on guns to 30 percent and tax ammunition at 50 percent. Anyone convicted of a hate crime would be barred from purchasing a weapon, and she would try to increase the minimum age for buying a weapon to 21 in all states. She would also push legislation to allow the survivors of gun violence to sue gun manufacturers.

“We’ve been talking for a long time about what we need to do,” Warren said.

Every candidate fielded questions from survivors of gun violence, family members of victims or young activists, some of whom wrestled back tears as they spoke. At one point, Harris walked into the crowd to grant a woman’s request for a hug. At another, Andrew Yang broke into tears.

Most argued that action should have been taken long ago. Some, including former vice president Joe Biden, pointed to the National Rifle Association’s influence over Republican politicians as a main barrier to action.

Republican lawmakers “should be exposed for what they refuse to do because they’re being intimidated,” Biden said.

He also said the Second Amendment is not the reason for a lack of action.

“The Second Amendment says that we can limit who can own a weapon, that we can limit what kind of gun you can own,” he said. “These guys will tell you ‘the tree of liberty is watered with the blood of patriots.’ Give me a break.’’

Conversations about gun violence have followed the candidates, sometimes literally, since last week. A gun rights advocate with a camera crew followed Washington Gov. Jay Inslee (D) as he roamed the Iowa State Fair on Saturday, asking him to define the “weapons of war” he wants to ban and say how his proposals were constitutional.

Inslee often tells audiences that he’s proud to have voted for the 1994 assault weapons ban, even though it cost him an election. At the fair, he told reporters that “Donald Trump and his Republican sycophants” are trying to make the issue go away.

“A weapon of war was what we defined in 1994,” Inslee said. “If you look at the research, there was a reduction in mass shootings where there were assault weapons used following the passage of that bill. That’s why I’m so angry at the Republican Party for kowtowing to the NRA.”

Inslee also argued for abolishing the filibuster to clear the way for gun control legislation, something Warren also brought up Saturday. And Sen. Bernie Sanders (I.-Vt.) reiterated his call to Senate Majority Leader Mitch McConnell (R-Ky.) — another frequent target of candidates at Saturday’s forum — to call the Senate back from its recess to vote on gun control legislation.

“If the American people want us to move aggressively in terms of gun safety legislation,” Sanders said. “Why aren’t we doing it?”

Annie Linskey and Emily Davies in Washington and David Weigel in Des Moines contributed to this report.