Hundreds of thousands of protesters demonstrated at Saturday's "March for Our Lives" rally in Washington, D.C., with a message for politicians who fail to tighten the nation's gun laws: "Vote them out."
"Stand for us, or beware, the voters are coming," Cameron Kasky, a now prominent figure in the student-led movement from Parkland, Florida, shouted from the stage in front of the Capitol.
Even the youngest speakers put lawmakers on notice. Eleven-year-old Naomi Wadler of Alexandria, Virginia, said, "We stand in the shadow of the Capitol, and we know we have seven short years until we too have the right to vote."
Kasky and his classmates organized the national rally on Washington's Pennsylvania Avenue after a former student of Parkland's Marjory Stoneman Douglas High School killed 17 students and staff members with an assault rifle on Valentine’s Day.
They predicted that the rally, which organizers claimed had drawn more than 850,000 people, would be a defining moment in the long-simmering national debate over gun control legislation. At that size, it matched last year's Women's March, making it one of the largest Washington protests since the Vietnam era and bolstering claims that the nation is ready to enact sweeping changes to its gun control laws.
And the young activists spurred a surge of rallies across the country, with more than 800 sister marches planned for every state in the country and around the world. Protesters took to the streets in Boston, Philadelphia, New York, Chicago, Dallas, Fort Worth, Los Angeles, San Diego, San Francisco and elsewhere, while marchers turned out in solidarity in London, Rome and Paris.
The demonstrators in Washington, bearing signs reading "We Are the Change," ''No More Silence" and "Keep NRA Money Out of Politics," stretched from the stage near the Capitol back toward the White House on a route that also took in the Trump International Hotel. President Donald Trump was in Florida at Mar-a-Lago for the weekend.
One of the most moving moments came from Emma Gonzalez, an outspoken Stoneman Douglas student who named all 17 victims of the shooting, but then used her time in the international spotlight to stand silent until an alarm beeped.
"Since the time that I came out here it has been 6 minutes and 20 seconds," she said then, the time it had taken for her classmates to be killed. "The shooter has ceased shooting, and will soon abandon his rifle, blend in with the students as they escape and walk free for an hour before arrest.
"Fight for your lives before it's someone else's job," she said.
The organizers of the rally are calling for a ban on the sale of assault rifles and large-capacity magazines and the extension of background checks to all gun purchases.
Shilpa Deshpande, attending the D.C. rally with her husband and 7-year-old son, approved.
"We feel like this is an easy problem to fix -- ban assault-style weapons," she told NBC. "My son told me how terrified he and his friends feel whenever they have a lockdown drill in school -- now they have it once every two weeks. We owe a safer world to our children."
Other Stoneman Douglas students echoed Kasky's challenge to politicians. David Hogg, another of the most recognizable faces from the high school, told NRA-supported lawmakers to "get your resumes ready."
Jaclyn Corin, who helped create the "March for Our Lives" campaign and was featured on the latest Time magazine cover, took on the president's campaign slogan, "Make America Great Again."
"We cannot keep America great if we cannot keep America safe," she said.
"Vote them out" chants rang through the audience.
The young protesters say their age and passion will set their initiative apart from previous attempts to enact stronger gun-control legislation. Stoneman Douglas survivor Sam Fuentas pushed back against critics who charge they are not old enough to take on the problem of guns.
"It is as if we need permission to ask our friends not to die. Lawmakers and politicians will scream guns are not the issue but can't look me in the eye," she said moments before throwing up onstage.
Fuentes, who was shot in the thigh, and hit in the leg and face by shrapnel, gathered herself before shouting: "I just threw up on international television and it feels great."
The Stoneman Douglas speakers shared their drive for gun control with others long affected by gun violence. When Corin finished speaking, she presented a special young guest: the granddaughter of Martin Luther King Jr.
"My grandfather had a dream....I have a dream that enough is enough," Yolanda Renee King, 9, said. "And that this should be a gun-free world. Period."
Teenagers from cities that have struggled with gun violence told of the pain it had brought their families, among them Trevon Bosley, a 19-year-old from Chicago, who led an impassioned chant: "Everyday shootings are everyday problems." Bosley's brother, Terrell, was shot to death outside of a church.
Seventeen-year-old Edna Chavez, whose brother was killed in South Los Angeles, said she learned to duck bullets before she learned to read, while 11-year-old Christopher Underwood, lost his brother in Brooklyn, New York.
"I would like to not worry about dying, and focus on math and science and playing basketball with my friends," he said.
The Florida students are determined to avoid the failures after the 2012 shootings at the Sandy Elementary School in Newtown, Connecticut, when 20 first-graders and six adults were gunned down. A bill to impose universal background checks was defeated in Congress.
Matthew Sotto's sister, Victoria, a first-grade teacher, was among those killed and he and other Connecticut residents criticized politicians who they say have failed the country with their inaction.
"Newtown wants change," Soto, 19, said. "Parkland wants change. The world wants change. Give it to us now."
The Sandy Hook principal, Dawn Hochsprung, also died in the 2012 shooting. Her daughter, Erica Lafferty, told a crowd in Hartford, Connecticut, Saturday, that the Parkland teenagers were "young people who have followed their voices and are not afraid to use them."
In between the speeches at the Washington rally, musicians Miley Cyrus, Demi Lovato, Ariana Grande, Andra Day and Common performed power-ballads for the crowd. Lin-Manuel Miranda and Ben Platt sang their new song "Found Tonight," a mashup of two of their Broadway songs in benefit of the "March for Our Lives" campaign. And Jennifer Hudson led an impromptu call-and-response sing-a-long for change.
The White House applauded the young activists for "exercising their First Amendment rights today," but the president himself remained silent on Twitter, his favorite outlet. In a statement to NBC News, deputy press secretary Lindsay Walters pointed to the Justice Department's decision on Friday to ban bump stocks to say that Trump had followed through on his promise to "ban devices that turn legal weapons into illegal machine guns."
At the sister rallies across the country, students, celebrities and survivors of the country's many mass shootings turned out. Some Stoneman Douglas survivors stayed in Florida, marching with thousands there. Students and alumni spoke, among them Sam Mayor, who was shot in the knee. "Change is overdue," she said.
Thousands swarmed Los Angeles, where signs read: "88 days until graduation, which one will be my last?" and "No more thoughts, no more prayers, time for action."
Former Beatle Paul McCartney marched in New York City, just steps away from where bandmate John Lennon was gunned down in 1980 outside the Dakota Apartments on Central Park West. Survivors of Sandy Hook and the Las Vegas shooting, which left 58 people dead at an outdoor concert, spoke.
Katie Taylor, 17, was there with three schoolmates from Somers High School in suburban Westchester County.
"We've sat through too many lock-down drills," Taylor said. "We've watched too many school shootings. We've done that. We're ready to change."
Tara Nash, a 37-year-old former classroom teacher who now works for New York City's Committee on Special Education, accused the NRA of bullying people. If anyone can force changes to gun laws it will be the students, she said.
"Their courage is unbelievable," she said. "It's really inspiring."
In Chicago, Sen. Dick Durbin commended the young people for teaching the adults. "I am not giving them a message," he said. "They are giving us a message."
Hundreds showed up to marches in both Forth Worth and Dallas, where protesters nearly filled City Hall Plaza in downtown Dallas and wrapped through the streets.
Saturday's event was the second major demonstration of the month. Students across the country walked out of their schools on March 14, a month to the day after the Florida massacre, sometimes defying principals and superintendents reluctant to sanction a political demonstration.
The teenagers from Parkland have tapped into a powerful current of pro-gun control sentiment that has been building for years, and have partnered with well-funded liberal groups such as Everytown for Gun Safety, the gun control advocacy group founded by former New York mayor and billionaire Michael Bloomberg.
They are savvy on social media and their demonstrations come amidst upheaval in American society, from the Women’s March to the Black Lives Matter and #MeToo movements.
"They’ve been very smart at taking some of the opposition's talking points and flipping them in ways that circulate pretty widely in the media and keep their message at the center," said Sasha Costanza-Chock, an associate professor of civic media in MIT’s Comparative Media Studies program in Cambridge, Massachusetts.
Polls indicate that public opinion nationwide may be shifting on an issue that has simmered for generations, and through dozens of mass shootings. A new poll conducted by The Associated Press-NORC Center for Public Affairs Research, found that 69 percent of Americans think gun laws in the United States should be tightened. That's up from 61 percent who said the same in October of 2016 and 55 percent when the AP first asked the question in October of 2013. Overall, 90 percent of Democrats, 50 percent of Republicans and 54 percent of gun owners now favor stricter gun control laws.
But even with claims of historic social momentum on the issue of gun control, the AP poll also found that nearly half of Americans do not expect elected officials to take action. Among the questions facing march organizers and participants will be how to translate the one-day event into meaningful legislative change.
One way is by channeling the current energy into mid-term congressional elections this fall. Students in Florida have focused on youth voter registration and there was a registration booth at the Saturday rally.
The Associated Press contributed to this report.