What does it take to mind-capture a fifth of the US in a few years? Fund a news outlet like Breitbart to make "the right-wing media system into an internally coherent, relatively insulated knowledge community, reinforcing the shared worldview of readers and shielding them from..." reality.
So in the world of observable, testable reality, Donald Trump’s accusations against his presidential predecessor are (under the most generous interpretation) unproved. The White House has presented zero evidence to substantiate Trump’s claims. But conservative media personalities like Hannity have aggressively and enthusiastically created an alternate reality in which Trump’s statement is self-evidently accurate and, as a consequence, former officials for Obama could now be in legal jeopardy.
... a new study by Columbia Journalism Review has ... identified Breitbart News as the gravitational locus of a conservative media galaxy that pumped out “disinformation” throughout the 2016 presidential campaign: “This turned the right-wing media system into an internally coherent, relatively insulated knowledge community, reinforcing the shared worldview of readers and shielding them from journalism that challenged it.”
What Columbia Journalism Review discovered ... is that conservative media outlets in the Trump era are far more effective at walling off their audience from any information that doesn’t comport with their preferred narratives.
“By repetition, variation, and circulation through many associated sites,” the review observed, “the network of sites make their claims familiar to readers, and this fluency with the core narrative gives credence to the incredible.” Once a source for disinformation is validated by like-minded sources, suddenly an allegation becomes “true” even if the person making it — in this case, the president of the United States — can’t put any factual weight behind what was said. Consumers of right-wing news see Sean Hannity go on the warpath against Obama associates on Twitter, then they read Breitbart’s write-up of Hannity’s tweetstorm, and subsequently they turn to Fox News and watch right-wing pundits talking about Obama’s “Soviet-level wrongdoing.”
... the self-reinforcing nature of the conservative media bubble means that external fact-checks carry no weight.
Another key thing to understand is that propaganda and disinformation enjoy a direct pipeline to the Oval Office, where it is consumed, validated, exploited and used to direct policy. Cutting though the nonsense that emanates from this toxic interplay between the president and his media enablers will be one of the greatest challenges... [emphasis mine]