When Young Mie Kim began studying political ads on Facebook in August of 2016—while Hillary Clinton was still leading the polls— few people had ever heard of the Russian propaganda group, Internet Research Agency[1]. Not even Facebook[2] itself understood how the group was manipulating the platform's users to influence the election. For Kim, a professor of journalism at the University of Wisconsin-Madison, the goal was to document the way the usual dark money groups target divisive election ads online, the kind that would be more strictly regulated if they appeared on TV. She never knew then she was walking into a crime scene.

Over the last year and a half, mounting revelations about Russian trolls' influence campaign on Facebook[3] have dramatically altered the scope and focus of Kim's work. In the course of her six-week study in 2016, Kim collected mounds of evidence about how the IRA and other suspicious groups sought to divide and target the US electorate in the days leading up to the election. Now, Kim is detailing those findings in a peer-reviewed paper[4] published in the journal Political Communication. The researchers couldn't find any trace, in federal records or online, of half of the 228 groups it tracked that purchased Facebook ads about controversial political issues in that six-week stretch. Of those so-called "suspicious" advertisers, one in six turned out to be associated with the Internet Research Agency, according to the list of accounts Facebook eventually provided to Congress. What's more, it shows these suspicious advertisers predominantly targeted voters in swing states like Wisconsin and Pennsylvania.

"I was shocked," says Kim, now a scholar in residence at the Campaign Legal Center, of the findings. "I sort of expected these dark money

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