Feds charge pizza gunman and fake news consumer Edgar Maddison Welch

What started as a fake news story resulted in a federal firearms charge Tuesday for a North Carolina man arrested after firing multiple shots inside a Washington pizzeria.

Edgar Maddison Welch, who cited a false narrative that prominent Democrats were operating a child sex-trafficking ring from the basement of Comet Ping Pong as his motivation for the armed incident last week, faces up to 10 years in prison and possible financial penalties for allegedly taking a firearm across state lines with the intent to commit a crime. Local charges have been dropped.

To some, Mr. Welch's story reflects the political tensions of a time in which Oxford Dictionaries named "post-truth" Word of the Year and President-elect Donald Trump and others kept professional fact-checkers on their toes. But the pizzeria incident also reflects a longer-term trend, as general distrust has swelled in the past few decades, say social scientists, making informed debate increasingly difficult for many Americans and introducing a challenge for professional journalists and policymakers alike.

Lucas Graves, an assistant professor at the University of Wisconsin, Madison in the School of Journalism and Mass Communication, says reasonable conversations about politics and public policy require a certain level of trust in the institutions that make those conversations possible. These institutions can include, for instance, government agencies and the news outlets that dissect government reports.

"We need to have agreed-upon sources of factual information that we can use to inform our discussion that aren’t seen as being slanted in any partisan way and that aren’t subject to political attack," Dr. Graves, whose book "Deciding What's True: The Rise of Political Fact-Checking in American Journalism" was published in September, tells The Christian Science Monitor in a phone interview.

This is not to say, however, that the establishment is beyond reproach. Mistakes, deliberate spin, and omissions do occur. Emphases can be misplaced. So there are, and should be, debates, Graves says, about the manner in which public facts are collected and assembled – just as the scientific community operates most effectively in an environment of robust, even prosecutorial, peer review.

But the scientific method does not justify a complete dismissal of established scientific knowledge about things like the influence humans have had on climate change, Graves says. It is similarly inappropriate to reject a journalistic consensus in the name of vigorous public debate or holding establishment leaders accountable for their words and deeds.

"The paradox is that you can only have distrust in the context of a larger trusting system," Graves says. "You have to trust something in order to be able to test somebody’s claims. You have to have some authority against which you can test them."

The authority Welch trusted was his own line of sight.

Welch told authorities he went to the pizzeria to "self-investigate" its rumored ties to a child sex-abuse ring led by Democratic presidential nominee Hillary Clinton and her campaign chief, John Podesta. He left after finding no evidence to support the bogus claim, police said. Although no one was injured in the armed confrontation, Welch's actions demonstrate how fake news spread online can manifest itself in real-world peril.

"We are at a dangerous place in American culture where a good percentage of people aren’t distinguishing what is a real news source based on real reporting and fact-checking and only reinforcing pre-existing ideas they have," Amanda Kleinman, a musician whose band has performed at the pizzeria, told The New York Times.

Welch's parents, Harry Welch Jr. and Terri Welch, attended his court hearing on Tuesday and said their son has a good heart.

"I want people to know he’s not the monster he’s portrayed to be," Terri Welch told The Washington Post.

"Fear can alter your perspective," she added later, "and I think this has driven a lot of the misconceptions about our son. We want to dispel those misconceptions so people will really know our son."

In a separate statement, the couple explained that their son has consistently volunteered his time and energy to help others, including a weeks-long stint in Haiti following a severe earthquake.

"We are a family of rescuers, and Maddison has been a part of that his entire life," they wrote.

Facebook, one of the key social media platforms on which fake news has spread, has stepped up efforts to fight the potentially damaging content, by curating articles from more reliable sources. The company's founder and chief executive, Mark Zuckerberg, said the platform would raise the bar for stories that appear in "related articles" links.

"A lot of misinformation is driven by financially motivated spam," Mr. Zuckerberg said. "We're looking into disrupting the economics with ads policies like the one we announced earlier this week, and better ad farm detection."

Still, there are other sources for fake news, including real people, even Mr. Trump's pick for national security adviser. The president-elect's transition team fired the son of Lt. Gen. Michael Flynn for tweeting a link to the fake-news story that seems to have inspired Welch's actions. But Lt. Gen. Flynn himself – whose nomination does not require Senate approval – has shared his son's interest in sharing conspiracy theories online.

Trump, too, has published baseless claims online. Even after Mrs. Clinton conceded her loss to him in the Electoral College, Trump asserted without evidence that the only reason Clinton won the popular vote was because "millions" voted illegally – a claim prominent media outlets promptly fact-checked.

President Obama warned during a news conference last month that fake news could pose a threat to the American political system.

"If we are not serious about facts and what's true and what's not ... if we can't discriminate between serious arguments and propaganda, then we have problems," he said, as the Hill reported. "If everything seems to be the same and no distinctions are made, then we won’t know what to protect. We won’t know what to fight for. And we can lose so much of what we’ve gained in terms of the kind of democratic freedoms and market-based economies and prosperity that we’ve come to take for granted."

This report includes material from Reuters and the Associated Press.