It was the moment the survivors of America’s plague of deadly school shootings got to have their say.

One week after the murder of 14 students and three of their teachers at Florida’s Marjory Stoneman High School in Parkland on Valentine’s Day, Cameron Kasky confronted Florida Senator Marco Rubio during a nationally televised debate.

“Can you tell me right now that you will not accept a single donation from the NRA [National Rifle Association]?” asked the Jewish teenager, who had been leaving a drama class when Nikolas Cruz began his killing spree.

Amid jeers and boos from the town hall audience, and under incessant questoning from the 17-year-old, Mr Rubio refused to rule out filling his campaign coffers with dollars from America’s politically powerful gun lobby.

Last month, Cameron’s father helped launch a campaign designed to ensure that US politicians such as the one-time presidential aspirant pay a price for continuing to accept the NRA’s largesse.

“NRA-supporting politicians have a decision to make: do they want to accept the NRA’s filthy blood money?” asked Jeff Kasky, a co-founder of Families vs Assault Rifles.

“If they do, we will shine a big fat spotlight on the fact that they are selling their vote to a nefarious, unprincipled organisation that exists only to enrich its executive board. It’s a vicious cycle between certain politicians and the NRA — and we are going to break that cycle.”

The organisation plans to “remove the NRA from our political system” and then fight for gun-control policies by amending the National Firearms Act of 1934 to ban, among other things, assault weapons.

It is soliciting $17 (£12.60) donations from the public, one dollar for each life lost in the Parkland shooting.

Although the political action committee will not endorse candidates, it will flood the airwaves in the run-up to November’s mid-term elections with negative advertising aimed at candidates supported by the NRA.

The NRA is officially non-partisan, but nearly 99 per cent of its vast war chest was spent backing Republican candidates, who overwhelmingly oppose gun control legislation, in the 2016 congressional elections.

Depending on how successful it is, Families vs Assault Rifles may help to bolster the Democrats in what is expected to be a difficult year for President Trump’s Republican party.

The elder Mr Kasky said that financial backers have already committed to give “multiples” of the donations the group receives.

“Wait until you see what we have in store for the NRA,” he proclaimed.

Thanks to the efforts of Mr Kasky’s son and fellow Parkland students, the gun lobby is on the back foot for the first time since Bill Clinton pushed a ban on assault weapons (which was later rolled back by George W Bush) through Congress nearly 25 years ago.

Cameron brought friends together at his home to set up the Never Again movement in the hours after the shootings. They soon joined other Parkland students who had begun to attract the attention of the news media.

After just over a month, Never Again had helped mobilise more than one million people to take to the streets of 62 American cities in the March for Our Lives, which drew crowds of 200,000 to Washington and 175,000 in New York.

Cameron’s feistiness has been on display from the outset.

“I’m safe,” he wrote on Facebook two hours after he had collected his brother, who has special needs, from his classroom as Cruz rampaged through their school. “Thank you to all the second amendment warriors who protected me,” he continued, referencing the clause in the US constitution which gun advocates claim protects their right to bear arms.

When Mr Trump addressed the NRA last month and pledged his fealty to the organisation, thus breaking a commitment to consider tighter gun laws made to the families in the wake of the shootings, Cameron accused the president of being “a professional liar who will say anything to appease whatever crowd he’s at”.

Such outspokeness has brought death threats from the far right and conspiracy theorist claims that Cameron and other Never Again founders are simply “crisis actors”.

Questioned by the media on the charges, the sassy teen had an answer for that too: “Well, if you had seen me in our school’s production of Fiddler on the Roof, you would know that nobody would pay me to act for anything.”