President Trump speaks during a campaign rally in Topeka, Kan., on Saturday. (Charlie Riedel/AP)

“You don’t hand matches to an arsonist,” President Trump declared at a rally in Topeka, Kan., on Saturday. “And you don’t give power to an angry left-wing mob.”

Trump was making what appears to be Republicans’ closing argument for the midterm elections: that the Democratic “resistance” to Trump’s presidency — particularly the hundreds of sexual assault survivors who confronted senators during the Brett Kavanaugh confirmation battle — is an “angry mob” and a danger to democracy.

He is not alone. Senate Majority Leader Mitch McConnell (R-Ky.), Sen. Chuck Grassley (R-Iowa) and Rep. Dave Brat (R-Va.) have all used the same phrase to describe Democrats, and GOP strategist Frank Luntz has advised a number of other candidates to use the term in their campaigns.

It takes a special kind of chutzpah for Trump, who has repeatedly urged supporters to violently attack protesters at his rallies, to call Democrats an “angry mob” — particularly when, just a few days earlier, he had a crowd of his own supporters chanting, “Lock her up.”

The fear of the angry mob has deeper roots, however. At some level, Americans have always worried that deliberative democracy could give way to violent, unreasoning mob rule. Fears of “tyranny of the majority” led James Madison to build extra checks and balances into the Constitution. And crowds of people have in fact done awful things in the past — the lynch mobs of the Jim Crow South or Adolf Hitler’s murderous brownshirts.

Over the past 50 years, though, the fear of angry mobs has also been weaponized for partisan and ideological purposes. Over and over again, American conservatives have raised the specter of the angry mob to justify their law-and-order policies and to delegitimize the social justice movements of their opponents — drawing a false parallel between social activism and mob violence that is itself a disservice to democracy.

Modern conservative rhetoric about crowds dates to 1896, when Gustave Le Bon’s popular book “The Crowd” was first translated into English. Le Bon, a French sociologist, was haunted by the violence of France’s many failed revolutions. He described crowds as a “servile flock” of “barbarians” characterized by “impulsiveness, irritability, [and] incapacity to reason” — behaviors otherwise observed in “inferior forms of evolution” such as “women, savages, and children.” Like Trump and McConnell, who have insisted that many Kavanaugh protesters were trained by George Soros, Le Bon also refused to believe crowds could act unless ordered to by their leaders.

Le Bon’s book, a bestseller in its time, has shaped popular understandings of crowd psychology ever since — even though it’s been largely discredited by over a century of psychological research. In fact, the latest work on mob psychology shows that “crowds are highly supportive, altruistic, friendly, and often fun places to be.” Crowds raise hundreds of millions of dollars for people with severe medical expenses not covered by insurance. They make concerts, festivals and weddings fun and enjoyable.

What’s more, even if participating in a collective effort emboldens them, people who join crowds remain very much in control of their actions. “An individual in a crowd behaves just as he would behave alone,” psychologist Floyd Allport argued in 1924, “only more so.” Nevertheless, the stereotype of the angry, unreasoning mob remains an object of terror and fascination in American culture. During the 1920s and 1930s, proto-fascist crowds — such as Ku Klux Klan parades or the pro-Nazi rallies of the German-American Bund — understandably came in for the most criticism. In reality, though, these crowds were menacing mostly because of the ideology of their members. A Klan rally was terrifying because it was made up of Klansmen, not because those Klansmen were together in a crowd.

But by the 1960s, fear of the angry mob became a tool to attack grass-roots organizing in the civil rights movement and student antiwar protests.

Opponents branded Martin Luther King Jr. an extremist and his followers an angry mob “inciting” their opponents “to hatred and violence.” In his 1963 “Letter from a Birmingham Jail,” King embraced parts of this characterization. The collective action of civil rights protesters, he argued, sparked a “creative tension” that would “help men to rise from the dark depths of prejudice and racism to the majestic heights of understanding and brotherhood.” Noting that Jesus, St. Paul, Martin Luther, Thomas Jefferson and Abraham Lincoln were all considered extremists during their lifetimes, King declared, “The question is not whether we will be extremists, but what kind of extremists we will be. Will we be extremists for hate, or will we be extremists for love? Will we be extremists for the preservation of injustice, or will we be extremists for the cause of justice?”

Likewise, student activists viewed collective action as the centerpiece of democratic life. As Tom Hayden explained in a 1962 manifesto, students hoped to transform America into a “participatory democracy” where decisions were made by deliberative public crowds. Politics, he argued, should have “the function of bringing people out of isolation and into community,” helping them find meaning in their lives.

But conservatives of the 1960s saw these activists as angry mobs undermining law and order — a view that led many conservatives to dehumanize protesters and even advocate violence against them. “If any demonstrator ever lays down in front of my car,” George Wallace declared in 1968, “it’ll be the last car he’ll ever lay down in front of.” After sending the National Guard to suppress a protest in 1970, Ronald Reagan agreed: “If it takes a bloodbath,” he said, “let’s get it over with.”

Just a few months later, National Guardsmen at Kent State University did just that, shooting four unarmed protesters at point-blank range. In the aftermath, a group of construction workers violently attacked protesters in New York City; they were so afraid of angry mobs that they had become one themselves.

Ultimately, the myth of the angry mob serves to justify conservatives’ indifference to the outrage of those they disagree with. Classifying protesters as a mob rather than citizens engaging in democratic activity allows Republicans to raise the specter of mob rule to avoid meeting their constituents’ needs. The result: They’re the ones doing violence to democracy. There’s nothing quite so irrational, so irresponsible or so dangerous as an entire political party trying to convince voters that sexual assault survivors confronting their senators constitute an “angry mob.”

Trump, at least, should have known better. After all, he is in office because the angry crowds of people who cheered at his campaign rallies were committed and rational enough to show up again at the polls. Likewise, if the GOP loses control of Congress in the midterm elections, it will be because the “angry left-wing mob” in the streets has transformed into a tidal wave of angry left-wing voters at the ballot box. Now that really would be something for Republicans to worry about.