By AJ Willingham, CNN

(CNN) -- It would be nice to think we could change the world with the click of a button.

But if that was all it took, thousands of people wouldn't have flooded the streets of cities around the country this weekend to call for gun law reform. They wouldn't have crowded buses and crafted signs and yelled at the top of their lungs and allowed strangers to crash at their houses and squeezed their bodies next to thousands of other bodies in hopes that their collective mass could finally tip the scales of change.

They wouldn't have shown up at all.

As the internet has reinvented the way we socialize and express ourselves, American activism has struggled to stay effective. Why march when you can share a Facebook post? After all, it's easier to discuss your opinions online or sign a virtual petition than it is to stand in line for the voting booth or sit through a town hall meeting.

This assumption is at the heart of slacktivism, the ill-defined and pejorative term that describes social media activism carried out with little personal effort.

But in 2018, that notion is dying with every person who marches and with every student who walks out of class in defiance of gun violence. For the #NeverAgain generation, raised in the age of Columbine and hashtags, the passive gestures of social media activism are not enough. They want tangible political action.

And slacktivism, as we know it, is over.

Breaking the cycle

The March for Our Lives crowd is distinctly bred online. It's not just the SpongeBob memes or their Tumblr-esque homemade signs. It's the way they organize, the way social media is used as a means rather than an end.

That in and of itself is an antidote to slacktivism, which sees no necessary action beyond a post, share or like. The #NeverAgain movement could have gone down that path -- after all, it is literally a hashtag.

But in the days following the February 14 shooting at Marjory Stoneman Douglas High School in Parkland, Florida, the persistence of student activists dominated the news cycle and broke the usual pattern of inaction that has stymied gun control activists for decades.

Within days of the tragedy, students from Stoneman Douglas boarded buses and went to Tallahassee, the state's capital, to demand action from lawmakers on gun control. The media, and the public's attention, followed. And within weeks the #NeverAgain movement, a series of school walkouts and Saturday's March for Our Lives rallies were already in the making.

At the March for Our Lives in Washington, Marjory Stoneman Douglas teacher Darren Levine said his students' efforts to organize the massive event were "surreal."

"It is everything that we can hope for as a teacher to see our young people take the steps that are needed to make real change," he said. "This isn't going to stop. I think that it is evident from these kids. They are not going to stop."

In Boston, MSD alumna Leslie Chiu put it simply: "This is not a moment," she said. "This is a movement."

Eyeing the end game

There is no one path to change. But the reality is, in a democratic society the impact of change is ultimately measured by voices and votes.

The people behind the #NeverAgain movement have made it clear their goal is not a march, or some viral fame. It is policy change. And that requires more of everything. More time, more effort, more showing up.

"First-time voters show up 18% of the time in midterm elections. Not anymore," Stoneman Douglas activist David Hogg said from a podium at the Washington march. "If you listen real close, you can hear the people in power shaking. They've gotten used to being protective of their position, the safety of inaction."

"We're going to make sure the best people get in our elections to run not as politicians but as Americans. Because this," he said gesturing to the US Capitol. "This is not cutting it."

To this generation of activists, that four-letter word -- VOTE -- is a battle cry stronger than any hashtag.

"We are too young to vote," 17-year-old Stoneman Douglas survivor Florence Yared told legislators at the Florida State House last month. "But soon we will be able to vote, and we will vote you out."

In Washington and at gatherings across the country, volunteers for HeadCount, a nonpartisan voting rights organization, roamed the crowds registering people to vote.

Jes Distad, a HeadCount team leader, said her team registered 200 people to vote in Atlanta alone. According to Distad, dozens of people also signed up for election alerts, and even more signed up to volunteer with HeadCount at future events.

"The momentum of just getting registered is great, but the next step is to make it out to the polls and actually put that registration to use," she said.

Changing minds, changing policy

So many things have happened since February 14, and so much is left to be done. On April 20, the anniversary of the 1999 Columbine shooting, #NeverAgain activists are planning another nationwide school walkout to follow the walkouts that took place on March 14.

Policy change and increasing voter turnout in the November midterm elections are the biggest, and most complex goals. But if nothing else, the #NeverAgain movement has slowly awakened legislative conversations about gun control that had stubbornly laid dormant even through some of the nation's worst shooting tragedies.

On Friday, Congress passed a $1.3 trillion spending package that incentivizes state and general authorities to report more data to the country's gun background check system. In early March, Florida Gov. Rick Scott signed a bill named after Marjory Stoneman Douglas High School that raised the minimum age to purchase a firearm to 21. The Illinois Senate recently passed a similar bill.

Gun rights advocates have tried to redirect the #NeverAgain conversation away from gun control measures and toward more gun-friendly actions, like arming teachers and increasing school security. While it's not the priority of most #NeverAgain activists, there has been movement there as well: The US House of Representatives passed a bill to fund more security at schools, although it didn't include any gun control measures.

Such action has been heartening for Leslie Gunn, a teacher who survived the 2012 mass shooting at Sandy Hook Elementary School in Newtown, Connecticut. Gunn was in the crowd at the Washington March for Our Lives event.

"We lost 20 children and six adults, 154 bullets in five minutes, and nothing was done," she said.

"We had voices and we advocated ... but if these kids now can make the voice that makes the change, we have to do this."

Looking to the past

Marching and making signs and shouting in the streets may seem fairly analog, but it's how Americans have gotten things done for decades. It only makes sense that this kind of physical presence would be the antithesis to wishy-washy political activism that begins and ends with a timeline scroll.

That's how the Women's Marches of 2017 did it, as a direct response to the 2016 presidential election. Despite pleas from both parties to show up, CNN estimated only 55% of voting-aged citizens actually cast a ballot that November, a 20-year low in voter turnout. For those devastated by the election's results, it was a wake-up call that whatever was being done for their causes wasn't enough. If the March for Our Lives put an end to slacktivism, it was the Women's March that opened the door for its departure.

And if the March for Our Lives makes any long-term difference, it will do so as a natural evolution of a form of democratic protest that has laid the foundation for change time and time again.

At the Atlanta March for Our Lives, Rep. John Lewis stood shoulder to shoulder with the throng. Lewis, 78, was a Freedom Rider, a civil rights activist who risked his life to march from Selma to Montgomery, Alabama, almost exactly 53 years ago.

"You must never give up. Never give in," he told the Atlanta crowd. "Keep your place and you are going to have a victory."

At the March for Our Lives event in Washington, the past and the future of activism -- of change in America -- converged in one little girl. Stoneman Douglas activist Jaclyn Corin gave the podium over to 9-year-old Yolanda Renee King, the granddaughter of Martin Luther King Jr.

"My grandfather had a dream that his four little children will not be judged by the color of their skin, but by the content of their character," she said, a breath away from where King uttered those same words 55 years ago. "I have a dream that enough is enough. And that this should be a gun-free world, period."

Looking at Saturday's marches in the context of Selma and Montgomery is not a perfect comparison. There was no widespread police violence this weekend, and the specter of institutionalized racial hatred was a talking point rather than an immediate threat. The #NeverAgain organizers know they have benefited from the mostly white face of their movement.

In fact, they have benefited from a lot of things: Corporations and celebrities lined up to be involved with the March, and the Womens March enjoyed the same kind of popular support. Both got their own designated Twitter hashtags, an emblem of the slacktivism they sought to exterminate.

John Lewis, on the other hand, got his skull bashed in by a policeman. King later was killed.

But the feeling of resonance between these two moments in time reflect similar visions: To affirm the value of their human lives, to be safe, to be heard.

Make no mistake, the students behind the #NeverAgain movement have succeeded in part because they stand on the shoulders of generations of activists who shrugged off the cloak of apathy, stepped out from behind the safety of platitudes and promises, and did what needed to be done.

They showed up.