Over the weekend, activists descended on Berkeley, California, and attacked peaceful protesters. But it wasn’t far-right white supremacists leading the violence this time, as was the case in Charlottesville, Virginia, a few weeks ago. It was left-wing “antifa” (short for “anti-fascist”) counterprotesters who assaulted people.

Mother Jones reporter Shane Bauer captured one of the attacks on video:

Antifa beat down apparent alt-righter. pic.twitter.com/WVdDJqLKmA — Shane Bauer (@shane_bauer) August 27, 2017

The attack on peaceful right-wing protesters has once again invigorated debates over the use of political violence — discussions that go back to a protester punching white nationalist Richard Spencer in the face during rallies against President Donald Trump’s inauguration. Such violence violates longstanding political norms in the US, and many Americans find any political violence deplorable — but it’s now a topic of conversation nonetheless.

The argument for antifa activists is that the current crop of right-wing protesters — which are partly but not entirely made up of neo-Nazis, KKK members, and other white supremacists and nationalists — are so extreme that they must be stopped swiftly and even violently. Antifa supporters worry that if these groups’ views aren’t completely robbed of any kind of platform, they could gain legitimacy — and take advantage of democratic ideals like free speech to, ironically, promote their undemocratic messages. Violence is one way to get them off the stage.

What this view misses is the backlash that may come from political violence: that such violence can reinforce right-wing views about the left. As Michael Kazin, a history professor at Georgetown University and editor of Dissent magazine, told me earlier this year, “[N]on-leftists often see [the left] as a disruptive, lawless force. Violence tends to confirm that view.”

Antifa’s violence plays into Trump’s hands

Some of this backlash is already happening. Consider how Trump himself reacted to Charlottesville. He drew a lot of (justified) criticism for arguing that “both sides” had been behind the violence in Charlottesville, instead of pinning the blame on the white supremacists who swarmed the Virginia city and caused mayhem.

But one reason Trump could draw up this false equivalence in the first place is because antifa protesters have been carrying out violence against right-wing groups for months now. As Peter Beinart reported in the Atlantic, antifa activists have violently protested right-wing speakers like Milo Yiannopoulos and conservative political scientist Charles Murray. In the Yiannopoulos protests in particular, antifa activists even threw explosive Molotov cocktails and other objects at police.

When far-left protesters act violently, it gives Trump and other conservatives more ammunition to draw equivalencies between the far left and far right — even if it is a false equivalence, given that America has a long history of racist violence and very little, by comparison, of left-wing violence.

And this argument seems to be working for a lot of people. A poll earlier this month by SurveyMonkey found that while 46 percent of US adults said far-right protesters were mostly to blame for the violence in Charlottesville, 40 percent agreed that the blame fell equally on both sides and another 9 percent blamed counterprotesters. (Although another poll found that a majority of Americans still disapproved of Trump’s reaction to Charlottesville.)

This wouldn’t be the first time violence has led to a conservative backlash in the US.

During the 1960s, there were hundreds of riots across America in protest of police brutality and in support of civil rights. Experts say the riots were a major contributor to the rise of “law and order” and “tough on crime” policies that followed in the coming decades. These policies made police more aggressive and filled America’s prisons to levels never seen before in US history. In short, the perception of lawlessness led both Americans and their politicians to demand more stringent law enforcement.

Omar Wasow, a political scientist at Princeton University, noted as much in a recent study:

In presidential elections, proximity to black-led nonviolent protests increased white Democratic vote-share whereas proximity to black-led violent protests caused substantively important declines and likely tipped the 1968 election from [Democrat] Hubert Humphrey to [Republican] Richard Nixon.

Violent protests led to a conservative backlash, while nonviolent demonstrations helped liberals.

The paper concludes, “[W]hile violence in response to repression is often justifiable, this research suggest it may not be strategic.”

One chart from Wasow’s study demonstrates the trend. It shows that “civil rights” became the “most important problem,” according to public polling, during peaceful protests in the mid-1960s (including the 1963 March on Washington topped by the “I Have a Dream” speech), while concerns about “social control” spiked when riots spread in the later part of the decade.

Antifa risks feeding another conservative backlash.

Trump himself ran on a “law and order” and “tough on crime” platform. If Trump can credibly argue that there is a lot of chaos and violence out there, that could empower him to carry out a crackdown. And with that crackdown could come both greater support for Trump and the enactment of his policies. It’s an outcome that antifa doesn’t want — but antifa’s approach to protest could very well fuel it.

Peaceful protest is effective

Antifa’s tactics also seem unnecessary, given the repeated success of peaceful protests.

Just this month, activists in Boston overwhelmed a right-wing rally — to the point the rally ended early — through almost entirely peaceful demonstrations.

Earlier this year, the Women’s Marches emboldened anti-Trump activists. Protests against the travel ban and Republican health care bill surely contributed to the defeats — or at least eventual watering down in the case of the travel ban — of these policies.

Over the past few years, peaceful Tea Party demonstrations empowered a new wave of conservatives. Occupy Wall Street protests brought the language of the “99 percent versus the 1 percent” to the political mainstream, arguably fueling Bernie Sanders’s surprisingly strong 2016 campaign. And in the 1950s and ’60s, Martin Luther King Jr. peacefully fostered a civil rights revolution — and he’s now revered by both the right and left for it.

This is how the US is supposed to work. Instead of resorting to force to work out differences, the American ideal is to demonstrate and head to the voting booth to affect change. America hasn’t always lived up to this standard — particularly during the Civil War and Jim Crow era of anti-black violence — but it’s the concept enshrined in First Amendment protections for free speech and for the right to peaceably assemble.

It’s effective too. US history shows that. Wasow’s study backs that up. And University of Denver researcher Erica Chenoweth, in her work on violent and nonviolent demonstrations worldwide, found nonviolent campaigns succeed much more often than violent ones.

Responding to right-wing protests with violence, then, isn’t just counterproductive; it’s unnecessary. The more effective response — by far — is peaceful demonstration.

Or as Michelle Obama put it, “When they go low, we go high.”