Anyone who has attempted public speaking, especially to make a contrary point in a room full of unsympathetic ears, will know that however much you prepare, there is a moment where you just have to jump on to the live wire of the moment, when your mouth starts to run while your brain fades to white.

That is what is so rousing about the speeches and media appearances made by the students of Marjory Stoneman Douglas high school since the mass shooting in Florida earlier this month. In nearly all of them their voices are breaking, they scream with rage, then they pause to gulp air and weep. They are riding the thinnest crest of a wave between abject grief, righteous anger and political will, seeming at any point as if they may by dumped by the weight of their own emotion. Yet despite this, they are able to argue their case in simple terms and identify the weakest link in the oft-perfected Republican script following a mass shooting.

Perhaps the most crucial thing that makes them effective advocates for change is the belief that change is possible

At a televised debate, for example, when Marco Rubio tried his usual “this is a tough issue, gun control won’t stop someone like this” spiel, student Cameron Kasky was meticulous. He first lavished praise on the senator for showing up and then asked him, repeatedly, whether he would refuse money from the NRA. It immediately exposed Rubio’s fraudulence, using sympathetic language with the students while still taking donations from rabid gun advocates. Rubio couldn’t find a workable response as jeers rang round the stadium.

Most shootings like this stay in the news for a few days, normally accompanied by a half-hearted gun control debate, before falling further and further down homepages. So how have these students been able to progress this issue when so many before them have failed?

Part of the reason is demographics: none of the children killed in the Sandy Hook school shooting of 2012 were over seven years old; these are middle-class students preparing for college. Their school was a place where political debate was encouraged, and there had been plenty of on-campus debates about gun rights when it was still an abstract issue for most of the students.

Of course, many of America’s most effective pieces of activism have come from its most disenfranchised citizens, but as Trevor Noah, host of the Daily Show, put it: “A lot of these kids come from wealthy backgrounds. The school in Parkland is in an affluent neighbourhood … This is people using their privilege, if that makes sense. Because these kids are like, ‘No, I don’t accept this world.’ And the parents and the politicians are like, ‘Well that’s not how it works.’ And they’re like, ‘Well you need to change it. I don’t care. I want to see the manager.’”

Both the media and the students themselves have suggested that the reason they’re being listened to is because they have grown up digital natives and they have been able to harness the power of social media. While it’s true that internet access will have exposed them to the power and techniques of activism, it does these teenagers a disservice to say they are merely wily online operatives. If anything, their success has been to avoid keeping protest inside echo chambers on Twitter and Snapchat, and reach out to normal Americans on TV news and mainstream shows like Ellen and the Today Show. Even in Britain, they have been a constant feature of Radio 4 news shows and the evening news on every channel. They have shrewdly understood that all media outlets are all hungry for access to the victims, and if they are willing to sacrifice their right to private grieving, there will not be a shortage of places willing to give them a platform.

Another smart move was to set the date of their planned nationwide anti-gun protest more than a month after the shooting, giving the story an extended news cycle and infuriating the gun lobby which had hoped that national anger would dissipate as it had in the past.

But perhaps the most crucial thing that makes them effective advocates for change is the basic belief that change is possible. One of the defining malaises of our age is the feeling that we can do nothing about the horrors we are exposed to every day. The American psychologist Martin Seligman called it “learned helplessness”, the documentarian Adam Curtis called it “oh dearism” – it is a feeling that intensifies over decades of repeated failures: if you have seen enough cases of police brutality, or horrifying wars in the Middle East or mass shootings you start to believe that nothing will ever change.

These students are not only too young to have lived through the many times this has happened before, they have also grown up in an era of radical change: the first black president, the first president with no political experience, the legalisation of gay marriage and, yes, the rise of social media and its ability to give a voice to anyone. They have not yet succumbed to the idea that nothing can be done.

One of their most popular chants, heard at rallies and vigils, ringing around the American news channels and no doubt in the White House, is “we have a voice”. On paper it seems like an odd phrase: it’s non-specific, it doesn’t demand anything of any power like most protest slogans do. But when you see it spat from the mouths of otherwise peaceful young people, you realise it’s not aimed at any one lawmaker, but the fabric of reality itself.

These survivors are experiencing their agency, destroying the very deep psychological barrier that says no person can change certain inalienable truths about American politics, reminding themselves that every great change in history happened just after a thousand missed opportunities when things stayed exactly the same.

• Sam Wolfson is a freelance journalist