The Mercers were keen to create a U.S.-based business to avoid bad optics and violating U.S. campaign finance rules, Wylie said. “They wanted to create an American brand,” he said.

The company’s early 2014 work turned on Bannon’s efforts to harness the power of anti-Establishment, far-right, and populist messaging, which would later be injected into Trump’s campaign. One year before Trump announced his candidacy, the firm had apparently already identified a swath of alienated white Americans. In focus groups centered around the 2014 midterms, voters responded to the suggestion of a border wall, racism towards African-Americans shrouded in the term “race realism,” and tactics intended to “drain the swamp” of Washington’s political elite. The firm also gauged opinions of Vladimir Putin. “The only foreign thing we tested was Putin,” Wylie noted. “It turns out, there’s a lot of Americans who really like this idea of a really strong authoritarian leader and people were quite defensive in focus groups of Putin’s invasion of Crimea.” (The Mercers did not respond to previous requests for comment.)

It is unclear what Bannon knew of Cambridge Analytica’s methods, which included harvesting data from a third-party app, allegedly created by academic Aleksandr Kogan, that was billed as a personality quiz. Because of Facebook’s lax guidelines at the time, Kogan was able to collect data on the friends of everyone who downloaded the app, too, expanding the pool of information available to Cambridge Analytica to include some 50 million Facebook profiles. Kogan has since spoken out, and said he is being used as a scapegoat by both Cambridge Analytica and Facebook. Facebook has since banned the parent company of Cambridge Analytica, Kogan, and Wylie for improperly sharing that data. (In a statement Wednesday, Facebook C.E.O. Mark Zuckerberg said that Facebook had changed its policy on third-party apps in 2014, and learned that Kogan and Cambridge Analytica had violated those rules in 2015. “It is against our policies for developers to share data without people’s consent, so we immediately banned Kogan’s app from our platform, and demanded that Kogan and Cambridge Analytica formally certify that they had deleted all improperly acquired data,” Zuckerberg said. According to Facebook, the company only learned of the breach after it was reported in The Guardian and The New York Times.)

The Trump campaign, which is already under investigation by the Department of Justice for possible collusion with Russia, could also feel the heat from Bannon’s involvement with Cambridge Analytica. Indeed, the various parties are inextricably linked: the Mercers funded Cambridge Analytica, the Trump campaign, and the pro-Trump news outlet Breitbart. The Trump campaign, in turn, hired Cambridge Analytica. Bannon served at Breitbart, Cambridge Analytica, and in the White House. Cambridge Analytica was sufficiently relevant to the Trump campaign’s efforts that, according to The Wall Street Journal, special counsel Robert Mueller has asked the firm to turn over the e-mails of any employees who worked on the campaign.

Unsurprisingly, Trumpworld has coolly distanced itself from the story, with an anonymous campaign official telling Politico that the 2020 re-election effort has no existing contracts with the data firm, and no plans to work with them in the future. The official said that the firm only “provided limited staffing” during the 2016 campaign, and the Trump campaign did not use the firm’s data. Back in 2016, however, Trump allies were singing a different tune. Then, Jared Kushner was more enthusiastic about the partnership which, according to election records, saw the Trump campaign pay Cambridge Analytica $5.9 million. “We found that Facebook and digital targeting were the most effective ways to reach the audiences,” Trump’s son-in-law told Forbes in a post-election, victory-lap interview. “After the primary, we started ramping up because we knew that doing a national campaign is different than doing a primary campaign. That was when we formalized the system because we had to ramp up for digital fund-raising. We brought in Cambridge Analytica.”