Part of the conspiracy feedback loop? Fox News Channel's Sean Hannity, shown speaking at a campaign rally for Republican presidential candidate Sen. Ted Cruz last year. (Rick Scuteri/AP)

To save Tinkerbell, all you had to do was clap your hands and really, really believe in fairies.

To send a conspiracy theory on its vicious way around the world, you need to do more than just believe. You need help.

Luckily for those who wanted to elect Donald Trump, that help was available during the presidential campaign, and still is. It comes from a collection of new right-wing hyperpartisan media outlets that are having a huge effect on politics.

Consider, for example, one outlandish idea from just last week: that the CIA hacked the Democratic National Committee’s emails, gave them to WikiLeaks and then framed Russia.

Business Insider traced it: from replies to the WikiLeaks Twitter account, through conservative radio and then Breitbart News, and out into the semi-mainstream — Sean Hannity on Fox News — all within 48 hours.

Similarly, the right-wing radio host Mark Levin may have started the evidence-free idea that President Barack Obama ordered the wiretapping of now-President Trump. It made its way quickly through the media ecosystem, after Trump saw it, apparently on Breitbart News.

Once the president tweets it, it’s undeniably news, picked up everywhere and re-amplified — especially by right-wing sites.

Derek Thompson of the Atlantic called this a “conspiracy-theory feedback loop.” And a very effective one it is.

A major new study, published in Columbia Journalism Review, detailed just how influential the new media ecosystem has become, calling it a determining factor in Trump’s election.

“A right-wing media network anchored around Breitbart developed as a distinct and insulated media system, using social media as a backbone to transmit a hyperpartisan perspective to the world,” the report concluded, after studying 1.25 million stories.

(Breitbart, of course, was run by — and maintains close ties to — Stephen K. Bannon, Trump’s chief strategist.)

As right-wing sites concentrated during the campaign on immigration stories — often with exaggerated or false claims about the dangers of refugees and immigrants — they also endlessly attacked Hillary Clinton over Benghazi and her use of a private email server.

These sites often traffic in “decontextualized truths, repeated falsehoods, and leaps of logic to create a fundamentally misleading view of the world,” the report said.

This brings to mind a Trump voter I met in northeast Pennsylvania who took right-wing talking points and put them in a blender. She told me she couldn’t trust Clinton because “I didn’t like how she stole those emails and it got people killed in Benghazi.”

This tainted media sphere not only set the conservative media agenda, “but also strongly influenced the broader media agenda, in particular coverage of Hillary Clinton.”

Kyle Pope, editor of CJR, explained: “On the right, there was an intense focus on Trump’s policies,” especially immigration.

But in covering Clinton, the right-wing sites often served as stenographers for conservative politicians.

And the mainstream media often went along for the ride, obsessing about the presidential horse race and failing to understand how all of this was resonating with voters. Plenty of excellent investigative reporting on Trump was published, but to some extent, it was drowned out by the noise.

There’s another way that the traditional press has allowed right-wing media to flourish — by moving too far to the left itself.

Mainstream newsrooms were once much more ideologically diverse, said Tom Rosenstiel, executive director of the American Press Institute.

“The best data out there shows that there are fewer Republicans working in traditional newsrooms and news generally than there used to be,” he told me.

As right-wing media sprang up over the past few decades, reporters and editors with more conservative beliefs migrated there. That left mainstream newsrooms with a high percentage of people identifying themselves as independent, a fair number of Democrats — and relatively few Republicans.

“That affects the discussion in newsrooms even when people are trying mightily to be fair,” Rosenstiel said.

Pope puts it more bluntly, referring to the “unarguable partisanship” he saw from some mainstream journalists as Nov. 8 neared, evident especially on social media. Favoring Clinton, they not only mocked Trump but also were unable to fathom that he might win.

Pope now sees “a huge corrective” underway, as journalists dig in, providing meaty accountability coverage of Trump and spending more time listening to Trump’s core of voters.

But whom are they reaching? Many Americans, especially on the right, have lost trust in mainstream media, which may be deeply flawed but at least is committed to factuality and truth.

Meanwhile, disinformation gains more of a dangerous foothold.

You can’t fight propaganda with standard journalism, Pope told me. Watchdogging the fake-news machinery and fact-checking relentlessly is part of his prescription.

Rosenstiel has suggested other measures: being more transparent about how we gather and verify the news; covering what’s important (not “barking at every car”); and using clearer labels to distinguish news from opinion.

I would add that news organizations have to acknowledge their own biases internally, and constantly report against them.

The CJR study concludes on a hopeful note: that a renaissance of legitimate journalism may be the result of everything that’s happened.

I’d love to think that, but it’s going to take hard work, the kind that doesn’t come easy to journalists: more openness to criticism, continued self-examination and willingness to change.

It won’t happen by closing our eyes and believing in fairies.

For more by Margaret Sullivan visit wapo.st/sullivan.