What if, early in the morning on Election Day in 2016, Mark Zuckerberg had used Facebook to broadcast “go-out-and-vote” reminders just to supporters of Hillary Clinton? Extrapolating from Facebook’s own published data, that might have given Mrs. Clinton a boost of 450,000 votes or more, with no one but Mr. Zuckerberg and a few cronies knowing about the manipulation.

“With no oversight whatsoever, I was left in a situation where I was trusted with immense influence in my spare time,” she wrote. “A manager on Strategic Response mused to myself that most of the world outside the West was effectively the Wild West with myself as the part-time dictator – he meant the statement as a compliment, but it illustrated the immense pressures upon me.”

Facebook ignored or was slow to act on evidence that fake accounts on its platform have been undermining elections and political affairs around the world, according to an explosive memo sent by a recently fired Facebook employee and obtained by BuzzFeed News.The 6,600-word memo, written by former Facebook data scientist Sophie Zhang, is filled with concrete examples of heads of government and political parties in Azerbaijan and Honduras using fake accounts or misrepresenting themselves to sway public opinion. In countries including India, Ukraine, Spain, Brazil, Bolivia, and Ecuador, she found evidence of coordinated campaigns of varying sizes to boost or hinder political candidates or outcomes, though she did not always conclude who was behind them.