Facebook's Sheryl Sandberg Axios How far can $42,800 take you on Facebook? Far enough to swing an election, says one expert.

Ben Kunz, the executive vice president of marketing and content at the media agency Mediassociates, says it could have cost at least this much to swing the 10,700 Michigan voters who tipped the scale in favor of Donald Trump in the 2016 presidential election.

"That's the scary power of Facebook. Its targeting is really, really powerful," he said. "People like to think they can't be persuaded, but the math says it works."

Kunz and his team made the estimate as part of a broader story by Business Insider in which Mediassociates and two other media agencies modeled the cost of using Facebook to reach voters in Wisconsin and Michigan with the intention of swaying their vote.

Facebook has said it discovered roughly $100,000 in ad buys between June 2015 and May 2017 associated with about 3,000 ads used by Russian groups to influence the outcome of the election. CNN reported that several of these ads targeted voters in Michigan, where Trump won by about 10,700 votes, and Wisconsin, which he won by roughly 22,700 votes.

While $42,800 may seem like a paltry amount to swing an election in a state, Facebook's advanced and granular targeting options can amplify the reach and engagement possible with that amount. Anyone looking to swing an election in Michigan could easily pinpoint and target undecided voters through data. After that, "it wouldn't cost much in ad spending to sway their opinions," Kunz said.

Mediassociates' model is based on two assumptions. One is a basic rule of thumb of digital advertising, which is that one out of every 2,000 people, or 0.05%, who view an ad will respond or act on the message. The second is that it is possible to target swing voters.

The model works backward from the exact number of votes by which Trump won both Wisconsin and Michigan — though it's possible that someone targeting swing voters could try to reach more people than that and therefore might spend more money on their campaign.

Trump won Michigan by 10,704 votes. Assuming only 0.05% of viewers will react to an ad, a person would need to aim for about 21.4 million ad impressions. Because Facebook ads cost about $2 for every 1,000 impressions, Kunz's team estimates that to sway this number of voters, a person would need a budget of $42,800.

"In reality, targeting this exact 'swing voter' population might take more effort, since some of your ads will reach the wrong people ... and competitors might be fighting you with similar tactics," Kunz told Business Insider. "But a clever political operator would just spend a little more. And for a few hundred grand, he or she could tip an entire presidential election."