(CNN)President Donald Trump's supporters were still rampaging through the US Capitol when the question arose: If these had been Black Lives Matter demonstrators instead of overwhelmingly White, militant Trump backers, how different would the police response have been?
Police respond differently when it's a left-wing protest, study finds
The Black Lives Matter Global Network hit the question hard in a statement following the Capitol siege.
"When Black people protest for our lives, we are all too often met by National Guard troops or police equipped with assault rifles, shields, tear gas and battle helmets," the group said in a statement. "Make no mistake, if the protesters were Black, we would have been tear gassed, battered, and perhaps shot."
Black Lives Matter protesters -- Black and White, old and young -- were indeed tear gassed on June 1 -- to clear an area around the White House so President Trump could walk to a nearby church to have his picture taken.
But police response to protests in the Trump era may depend as much on the politics of the demonstrators as on their race, experts say.
And demonstrators on both the right and the left see police as siding with right-wing protestors, according to a policing expert.
"The right-leaning protesters will say police used force against Black Lives Matter and not them because they are on the 'right' side, the same side -- they 'back the blue,' they are pro-police," said Ed Maguire, a criminal justice professor at Arizona State University. "The left-leaning protesters believe the same thing: that the police are on the side politically of the right."
"What we saw with the Black Lives Matter protests was a really massive over-response, and what we saw at the Capitol was a similarly massive under-response," he said.
The conduct of some police officers during the Capitol siege highlights Maguire's point.
At least two Capitol police officers were suspended for their behavior during the incident. According to Democratic Rep. Tim Ryan of Ohio, one of the suspended officers took a selfie with members of the mob, while another wore a "Make America Great Again" hat and directed people around the Capitol building.
At least two off-duty police officers from Virginia have been arrested in connection with the breach of the Capitol and face federal charges, including "violent entry and disorderly conduct on Capitol grounds."
Officers from New York, Philadelphia, Seattle and Texas are also under investigation by their departments.
Left-leaning protesters are significantly more likely to be arrested than right-leaning ones, according to a 2020 study from Lesley Wood, an associate professor of sociology at York University in Toronto.
Wood studied media reports of arrests at 64 demonstrations in the United States in 2017 and 2018.
She bracketed anti-abortion demonstrations and those backing Confederate statues, White supremacy and President Trump, for example, as being right-wing, while considering demonstrations in favor of gun control, immigration and civil rights, among others, to be left-wing.
She focused on protests that face counter-protests because they are "more likely to be violent, and present special challenges for the police," she wrote in the study, "Policing Counter-Protest," published in the journal Sociology Compass in 2020.
She found that 10 times as many left-wing protesters were arrested as right-wing protesters: 279 from the left and 26 on the right. The political identity of the other 38 people arrested in the 2017-2018 US demonstrations was unknown.
"Police in North Carolina, Virginia and Louisiana were more likely to arrest those condemning Confederate statues than those protecting them," Wood wrote. "Police in Georgia arrested anti-fascists rather than neo-Nazis; and across the country arrested anti-racists and Trump opponents rather than Islamaphobes [sic] and Trump supporters."
The size of demonstrations is often contested, but the left-wing protests Wood studied tended to be larger than the right-wing ones. Even with the size of protests difficult to pin down exactly, left-leaning activists appeared to be about two-and-a-half times more likely than right-leaning ones to be arrested, she told CNN.
"It is really striking that you see that left-wingers are arrested at a much greater level," she said.
Wood underlined a key factor: Police have different views of right-leaning and left-leaning demonstrators.
"The logic of policing protest has been one of threat assessment, and they tend to see left-wing protest as more threatening than right-wing," she said in an interview with CNN.
"That is tied to many things, such as race," Wood wrote. "Groups that are critical of the police are seen as more threatening. That helps explain why Black Lives Matter, which was critical of the police and black-led, was seen as threatening."
Wood wrote that police agencies aim to be "professional, cost-effective and legitimate" in protest situations, valuing "political neutrality, permits and negotiation between police and organizers."
Months of demonstrations and counter-demonstrations by the right-wing Patriot Prayer group and left-wing groups including antifa and members of religious and human rights organizations in Portland, Oregon, in 2017 and 2018 provided a case study for Wood.
"While the Patriot Prayer activists worked with the police, the police had no success in communicating with the anti-fascist leadership," she wrote. "Police perceive protesters who refuse to negotiate, do not have a centralized leader, and hide their identity from police, as more threatening."
"Because police repress on the basis of their understanding of threat, it means that left-wing protesters, racialized protesters, protesters who are seen as ideological or irrational, are more likely to be arrested and have militarized tactics used against them, such as tear gas and pepper spray," Wood told CNN.
But Bill Johnson, executive director of the National Association of Police Organizations, questioned some of Wood's conclusions.
"The author explains that leftist counter-protesters deliberately utilize the tactic of 'no platforming,' which is defined thus: 'No Platforming means disrupting rallies that aim to promote racist or fascist ideologies by organizing such large counter protests that the planned speeches cannot be heard,'" Johnson told CNN by email.
"If I'm reading the study correctly, leftist counter-protesters are thus more likely to be arrested because by definition they are breaking the law by deliberately trying to shut down lawfully permitted rightist demonstrations," Johnson said.
Johnson also pointed out that the left-wing protesters include, in Wood's words, "communist, anarchist and socialist antifascists."
Those ideologies, Johnson said, "share a common thread of wishing to tear down an existing legal/political/social structure and replace it with something else. By definition, then, we would expect protesters who are adherents of those ideologies to overtly present anti-social behavior to a greater degree and extent than other groups who do not share that same wish. And thus we would expect more arrests."
And he noted that Wood's paper includes little data about the reason for protester arrests or the results.
"There is no indication of the judicial disposition of the charges: Were they sustained? Shown to be false? That would seem to be an important bit of data," Johnson said.
The United States has a history of policing Black-led events more than White-led ones.
A landmark study of more than 15,000 US protests during the Civil Rights period and the decades after it found that, at some points in that era, police were more likely to be present and to take action at Black-led events than predominantly White ones.
But the paper, "Protesting While Black? The Differential Policing of American Activism, 1960 to 1990," published in the American Sociological Review in 2011, also found that in many years, the race of protesters appeared to make no difference to policing.
Police arrested 61 people on January 6, the day the Capitol was overrun by Trump supporters. More people have been arrested in connection with the storming of the building since then.
A CNN analysis found no less than nine occasions when police arrested more Washington demonstrators in a single day than they did on January 6, ranging from 133 LGBTQ activists at the Supreme Court in October 2019, to 575 protesters against Trump Administration immigration policy in June 2018.
On June 1, 2020 -- the day of President Trump's photo op at the church near the White House -- police arrested 316 people.
CNN's list is not comprehensive, but all nine demonstrations share a common factor: they were left-leaning demonstrations.