• A cottage industry of fact-checkers grew into a behemoth after 2016, bankrolled by tech companies’ donations to nonprofit fact-checking networks.

• Exclusive interviews with 20 trust and safety workers at major social media companies expose an inconsistent, ineffective system that was no match for the volume of content it was tasked with reviewing.

• Instead of being guided by truth, “decisions were driven by internal politics or vague corporate mandates.”

• Leadership often had no relevant expertise; at one company, fact-checking policies were crafted by a middle manager with a degree in acting. In the words of one employee, “there was a lot of posturing.”

Earlier this year, Meta pulled the plug on its US fact-checking program. Google now refuses to add fact-checks to Search and YouTube. Nearly a decade of work — hundreds of millions of dollars spent, thousands of people hired — is gone, essentially overnight, and for good reason.