Kaden Pagani, 8, marches during a Black Lives Matter protest in Oakland, Calif., on July 21. (Noah Berger/Reuters)

BATON ROUGE — In Detroit, the marchers chanted the name of Aiyana Stanley-Jones, the 7-year-old girl fatally shot by police in 2010. In Oakland, demonstrators chained themselves to the doors of the police department. In New York, massive banners were uncurled from atop the entrance to the Holland Tunnel declaring “Black Lives Matter” and “Fund Black Futures.”

As much of the nation on Thursday focused its eyes on Cleveland for the final night of the Republican National Convention, protesters with the Movement for Black Lives — often referred to as the Black Lives Matter protest movement — took to the streets in more than two dozen cities, one of the largest acts of joint protest in the movement’s two-year history.

The show of strength — with hundreds of participants pouring into the streets — comes as leaders of the protest movement say they’ve doubled down on their mission in light of the fatal police shootings of Alton Sterling in Baton Rouge and Philando Castile in a St. Paul, Minn., suburb — black men whose deaths were captured on video.

“It’s a national call for the divestment from police, and the reinvestment into communities of color,” said Kayla Reed, an activist and organizer in St. Louis who began protesting after the 2014 police shooting of Michael Brown in Ferguson, Mo. “People have been re-exposed to a level of trauma these last few weeks. There is this new wave of consciousness; there was a resurgence of people wanting to take action.”

“This is the moment where we want to lift back up the reality that in two years, nothing has actually changed,” she added.

The coordinated national demonstrations are part of a pivotal moment for the protest movement. It has been four years since the creation of the #BlackLivesMatter rallying cry, and nearly two years since the deaths of Brown, Eric Garner, John Crawford and Tamir Rice thrust thousands into U.S. streets to protest police killings.

But in the hours and days after the murder earlier this month of five police officers in Dallas — a targeted shooting by a lone-wolf gunman who, according to police, claimed to have been enraged by police killings of black men — some declared the incident a crippling development for the protest movement.

“Black Lives Matter Was Gaining Ground. Then a Sniper Opened Fire,” screamed a New York Times headline for an article that described the Dallas shooting as “perhaps the biggest crisis in [the protest movement’s] short history.” Critics again blasted the protests after another shooting of officers, which left three police dead in Baton Rouge on Sunday, even as protest groups and leaders were quick to condemn the violence. In an editorial earlier this week, USA Today chided the activists for “clinging to false narratives,” such as the chant “Hands Up, Don’t Shoot” — a rallying cry popularized after the police shooting of Brown.

Just one day after the editorial was published, video of a police officer in Florida shooting Charles Kinsey, who was attempting to help an autistic man, went viral. Kinsey had his hands up and shouted to the officer not to shoot. The officer fired three times, wounding Kinsey.

Despite two years of discussion and protests, police shootings have not become more rare nationally. A Washington Post analysis found that police officers were on pace to shoot more people in 2016 than they did in 2015 — and that black Americans remain 2 1/2 times as likely to be shot and killed by police officers.

“We have no choice but to keep going,” said Brittany Packnett, an activist who was among those who attended a meeting to discuss race and policing convened by President Obama last week. She said recent police shootings have prompted a new wave of energized participants to join the protest movement. “If one of the central demands of the movement is to stop killing us, and they’re still killing us, than we don’t get to stop either.”

In the past week, thousands across the nation have used a tool provided by Campaign Zero, a policy-oriented activist collective that Packnett co-founded, to contact their local elected officials to demand police reforms. Local chapters of protest and activist groups in several cities said this week that they’ve seen an uptick in interest from new members that mirrors the mobilization that occurred after it was announced that Darren Wilson, the officer who killed Brown, would not be charged with a crime.

“It is not our goal to return to where we were before Alton Sterling was shot,” the Rev. Lee Wesley, pastor at Community Bible Baptist Church in Baton Rouge, said Sunday. Wesley announced plans to form a coalition to discuss solutions to the city’s racial divide, including implementing a community policing initiative funded by the Department of Justice. “It is not our goal to get back to business as usual. It is our goal to move forward.”

In Baton Rouge, activists in the city are torn. On the one hand, they are trying to hold onto the momentum they feel they’ve gained in the past two weeks. On the other, Baton Rouge is in mourning, and the officers killed warrant respect. And, they say, they worry the city remains a powder keg.

“Law enforcement was very aggressive during the protests” that occurred after Sterling’s death, said Arthur Reed, an activist whose group helped obtained the video of Sterling’s shooting. “Now, when they have lost police they have loved … more protests could lead to potential dangerous situations.”

While demonstrations had come to a halt following Sunday’s shooting of officers, by Tuesday night, Reed and a few others had returned to their protest posts in front of Baton Rouge police headquarters. The demonstration was to be a subdued affair — just about 10 people. “Respectful,” Reed said, “but serious.”

“You are mourning, and we feel that pain,” he said, referring to police. “But we want you to feel the pain of the Sterling’s loss. That is not going away.”

Nationally, many activists have been offended in recent days by a town hall hosted by Obama, which they said was meant to calm unrest but overlooked substantive discussion of solutions, as well as an open letter to law enforcement that the president published earlier this week.

“The amount of violence experienced by police officers is not comparable to that which they inflict,” wrote Mychal Denzel Smith, a writer and activist, on The Post’s PostEverything blog Thursday. “So when the president writes an official letter to law enforcement that glosses over all of this in an attempt to offer his ‘full-throated support’ for them, he continues the mythologizing of police heroism that protects them from prosecution and reform.”

Meanwhile, Thursday night’s speech by Donald Trump as he accepted the Republican presidential nomination underscored for many of the activists the urgency of their demands.

“While our movement envisions a bright future where everyone is treated with dignity and respect, Trump is proposing a new, dark age where police have carte blanche authority to terrorize our communities,” said Alicia Garza, one of the co-founders of #BlackLivesMatter, the activist network that shares a name with the broad protest movement, in a statement Thursday night.

Trump’s 75-minute address focused heavily on “lawlessness” and implied that the protest movement has led to an increase in attacks on officers. Many of the activists, who opted to skip protesting at the convention but are expected to conduct some protest actions at the Democratic convention next week, saw the speech as a declaration of war against their movement.

“His doublespeak belies his true nature: a charlatan who will embolden racists and destroy communities of color. He is a disgrace,” said Patrisse Cullors, another #BlackLivesMatter co-founder. “White people of conscience must forcefully reject this hatred immediately.”