A gun research initiative spearheaded by President Obama in response to the Sandy Hook massacre that left 20 children dead in 2012 has been effectively suspended by the National Institutes of Health (NIH).

The end of the program – which ensured funding for scientists looking into the causes of gun violence – could silence research into a deadly phenomenon that claims the lives of more than 33,000 Americans every year.

The funding initiative, which awarded US$18 million to 22 research projects over the last three years, has reportedly been left to lapse since January, when the NIH stopped accepting proposals from scientists.

Renewal of the program – which was originally only intended to last three years from its inception in late 2013 – is still a possibility under consideration, according to a NIH spokesperson contacted by Meredith Watson at Science, but there's no timeline in place for such a decision.

Without that kind of reprieve, the initiative – and the understandings it enabled – may effectively be over.

That's a big problem, according to firearms experts, because while it may have been years since Obama directed US scientific agencies to look into the problem, those years have not been kind.

By many measures, gun violence has worsened since Sandy Hook took place – with mass shootings tripling between 2011 and 2014, gun suicides increasing by 30 percent over the last 10 years, and firearm fatalities on the whole steadily rising every year between 2011 and 2015.

In other words, more people are dying from guns in the US than when the NIH first encouraged scientists to look into why this deadly scourge is happening – and find ways to prevent it – so it looks like the researchers' work is far from done.

"It's really critically important to renew that program if we want more firearms research," developmental psychologist Rina Das Eiden from the State University of New York at Buffalo explained to Science.

Predictably, that sentiment is not shared by gun rights advocates, who maintain that federal monies aren't needed to bolster robust independent examinations of why gun deaths in the US occur (at a rate 25 times the average of other high-income countries).

"Private groups and foundations donate millions of dollars to fund firearm research every year," NRA spokesperson Lars Dalseide told Science.

"When the government gets involved, and political agendas are allowed to supersede scientific analysis, the end product is nothing but a waste of tax-payer money."

As disappointing as the stalled funding program is, though, it actually reflects something of a return to normality for gun research in the US, at least in terms of recent history.

That's because of a gun-lobby-backed 1996 bill called the Dickey Amendment, which saw Congress prevent the Centres for Disease Control and Prevention (CDC) and other bodies from allocating any federal money to "advocate for or promote gun control".

That prohibition, worded as it was, stymied federally funded scientific research into gun deaths for almost two decades – leading a study published earlier in the year to discover that, "[i]n relation to mortality rates, gun violence research was the least-researched cause of death".

Unless something turns up soon and the NIH's funding program gets its green light renewed, that state of affairs is unlikely to change – and the future's grim statistics will continue to go unexplained.