Shield walls have been used on battlefields from ancient Sparta to Hastings in 1066 — and now on the streets of Portland, Oregon.
Protesters come nightly carrying homemade shields and protective armor, forming a wall in the streets, ready to test police officers who stand between the demonstrators and their targets for mayhem.
But the protesters also combine the Space Age with the medieval, arming themselves with lasers, used to dazzle cameras and distract police officers. Green lasers are most common, but blue lasers are the most dangerous. They are hot enough to ignite paper and, according to police, to scorch an officer’s skin.
The tactics of protest have evolved greatly since the peaceful marches of the civil rights era and the more violent days of the 1970s. They also have gone worldwide, with anti-police protesters in Portland and Seattle learning from the anti-communist protests in Hong Kong and others elsewhere.
That means black clothing, which helps create anonymity in the crowd, making it tough for authorities to pin a particular act on a particular person. Umbrellas are used to block cameras, and fireworks and smoke are deployed to confuse. Even leaf blowers have a use: to push tear gas away from protesters. All those tactics got their start elsewhere but have been used to great effect on the streets of the U.S.
“I haven’t done a systematic analysis yet, but clearly there is a lot of diffusion happening, particularly in terms of defense against less lethal weapons,” said Lesley Wood, a sociologist at York University in Canada who studies protest movements and policing.
The vast majority of demonstrations this year in the U.S. have been peaceful.
Dana R. Fisher, a sociology professor at the University of Maryland who studies protest movements, conducted a survey of the crowd reliving Martin Luther King Jr.’s historic march on Washington on Aug. 28. She found that only a third said they had engaged in “direct action” demonstrations over the past year.
In Portland, while thousands have marched for racial justice, those committed to chaos number only a couple of hundred, though they turn out night after night prepared to battle police. It’s usually easy to tell who they are.
“Folks who are expecting to get arrested, they gear up, they write numbers for people to bail them out on their arm,” Ms. Fisher said.
Some of the gear has been standard for decades, such as bottles filled with gasoline and covered with a wick — the Molotov cocktail. Throwing rocks from the street has been a mainstay of protests for far longer.
Police say they also have confiscated stun guns, batons, knives and the occasional firearm. Federal authorities, who deployed agents and officers to Portland, reported facing sledgehammers, metal pipes and improvised explosive devices.
Balloons filled with urine or feces also have been lobbed.
And then there are the lasers.
Most are green. Although they are sold as laser pointers, they are often powerful enough to injure the eyes. The Department of Homeland Security said its agents and officers deployed to Portland have sustained more than 100 eye injuries.
Police have nabbed some laser operator suspects.
Federal prosecutors last week charged Hugo Ryan Berteau-Pavy, 26, with firing a laser at the Multnomah County Justice Center during a June 13 demonstration.
An officer on the roof of the center tracked Mr. Berteau-Pavy through the crowd, according to court documents, and then watched as he and other protesters marched to Mayor Ted Wheeler’s home and shone the laser at his residence and other homes in the neighborhood. Mr. Berteau-Pavy was arrested with a green laser in his pocket.
Local prosecutors did not pursue the case, so federal officers stepped in.
The local district attorney did pursue charges in a case accusing Bryan M. Kelley of firing a blue laser into officers’ eyes as protesters broke into Portland City Hall in late August.
“Law enforcement found the laser was so powerful that it would burn through paper and cause dry material to catch fire,” the district attorney’s office said.
Prosecutors said Mr. Kelley admitted he knew the laser was advertised as capable of “burning,” and he knew it could damage eyes.
Protests and mayhem continued in Portland this weekend with what police described as a “large fire” set Sunday night on mattresses in the street near a police station and demonstrators chanting “Burn it down.”
When the fire became a danger, police alerted protesters that they were bringing in the fire department. Most demonstrators made way for the firefighters to extinguish the blaze.
During the evening, 15 people were arrested.
Police described the equipment they confiscated, including a stun gun, a baton, body armor, a sling shot and a prepared Molotov cocktail — a dish detergent bottle with a wick taped to the top, ready to be lit and thrown.
Portland police regularly say the unruly crowd is full of people wearing body armor and gas masks or goggles and carrying homemade shields, seemingly singling them out from more mundane protesters.
Ms. Wood, the professor at York University, said there is a long history of police trying to divide “good” and “bad” protesters.
“Unfortunately, this perception of ‘bad’ protesters relies on stereotypes and assumptions — often targeting young, Black, countercultural activists, and those who won’t cooperate quickly with police,” she told The Washington Times.
“In an atmosphere of distrust and polarization, many more protesters may be unwilling to cooperate and are thus perceived as ‘bad,’ escalating the conflict,” she said.
On Sunday, police in Portland said they tried to deescalate the situation by, for example, pulling back officers after the fire was extinguished.
Protesters say that is not always the case. They complain of hair-trigger responses by officers and use Twitter to identify those they believe are more likely to become aggressive with demonstrators.
A typical evening will start with the committed demonstrators gathering at a park and picking a destination for the evening. Police stations and public buildings have been prominent targets, but so was the Portland mayor’s apartment building.
Police, through a loudspeaker, will tell the protesters to remain peaceful and stay off certain property or fences. But protesters will rattle a fence or encroach on the off-limits property. Officers respond either by marching in force or by deploying less-lethal weapons, sometimes including tear gas.
“It’s almost like a dance between protesters and law enforcement,” said Ms. Fisher, the University of Maryland professor.
A key moment comes when protesters lob rocks or toss tear gas canisters back at officers.
“Once something’s been thrown at police, things escalate from there,” she said.
Ms. Fisher said the mayhem sometimes is a miscalculation. Fireworks aren’t used intentionally to set fires, but it can happen, and “once something gets on fire, everything escalates.”
The weaponry can spur a kind of arms race.
When rioters targeted the federal courthouse in downtown Portland, federal agents and officers were quick to deploy tear gas. A group dubbed the Portland Dads soon brought leaf blowers to push the tear gas cloud back toward the police.
When coordinated, the strategy worked perfectly. The officers were limited by their need to defend a specific piece of ground, making them vulnerable to the retaliation.
Within a couple of days, though, federal authorities brought leaf blowers of their own to control the direction of the gas cloud.
Portland has pioneered some moves such as the Wall of Moms, a group of self-proclaimed mothers who stood as a first line of protesters, singing lullabies and hoping to serve as protection for those behind them. Ms. Fisher said she could see that tactic spreading to other protests.
Tactics are shared online, sometimes through social media posts but also through websites such as CrimethInc.com, which serves as a kind of Consumer Reports guide with articles such as “A Demonstrator’s Guide to Helmets” and “Protocols for Common Injuries From Police Weapons.”
“When you’re choosing a leaf blower, make sure it has a good fan and a wireless power source,” the site advises. “Leaf blowers work well in combination with umbrellas and shields. While the shields protect demonstrators against impact munitions, the leaf blowers keep the gas moving away from protesters until someone can run up and extinguish the canister or throw it back at the assaulters who shot it. Teamwork!”
CrimethInc., which calls itself “a decentralized network pledged to anonymous collective action,” also gives advice on how to hold a shield to absorb a police charge and how to use a lacrosse stick to pick up and fire tear gas canisters back at police.
One irony of the protests is that demonstrators, whose stated goal was to draw attention to policing tactics, have brought much scrutiny on their own moves.
They debate tactics among themselves, even in the heat of a protest, arguing with one another over megaphones over whether to attempt some action such as tearing down a fence.
Other times, the debate happens online.
After this weekend’s arrests in Portland — Saturday’s 59 arrests was a one-day record during the 100 days of mayhem — the Pacific Northwest Youth Liberation Front questioned why protesters always marched straight at police.
“Instead of marching straight to the riot line, head-first into clouds of tear gas and violent arrests, let’s move AWAY from the cops,” the outfit said in a Twitter post.
It also suggested picking other targets: “There are certainly hundreds of corporations that fund or profit off of policing, prisons, ICE, etc., that haven’t received enough attention at protests.”
Ms. Fisher said police in Portland, including federal officers, used confrontational tactics to disperse crowds and hoped to dissuade people from coming out to protest.
“In times when people are feeling really outraged and upset, that doesn’t actually work,” she said. “Research shows us when a crowd has hit a certain boiling point with dissatisfaction with the status quo, if you try to disperse by being more aggressive, you end up with larger crowds.”