News that Cambridge Analytica CEO Alexander Nix approached Wikileaks founder Julian Assange last year to exploit Hillary Clinton’s private emails has amplified questions about Cambridge's role in President Trump's 2016 campaign.

Shortly after The Daily Beast reported Nix’s contact with Assange Wednesday, the Trump campaign’s executive director sought to downplay Cambridge's role. Michael Glassner said in a statement that the Republican National Committee was the campaign’s primary source of voter data. “Any claims that voter data from any other source played a key role in the victory are false,” Michael Glassner wrote. The statement did not respond to reporting in WIRED and elsewhere revealing a close relationship between the Trump campaign and Cambridge staffers. Cambridge did not respond to WIRED's request for comment.

So, what gives? Such he-said-she-said battles are usually better left to Beltway happy hours. But as Congress and special investigator Robert Mueller turn their spotlights on Cambridge Analytica in their probes into Russian meddling in the 2016 election, it’s essential to get the facts straight about what the firm did---and didn’t---do for the Trump campaign.

Here’s what we know.

Cambridge worked both for the Trump campaign and a Trump-aligned Super PAC. In June 2016, Cambridge sent three staffers, led by chief product officer Matt Oczkowski, to the campaign’s San Antonio office. Oczkowski’s team eventually grew to 13 people, working under Trump digital director Brad Parscale and alongside his staff and outside consultants. According to Parscale, the Cambridge staff provided useful analysis of data about the American electorate. They did not, however, provide the raw data---things like demographic information, contact information, and data about how voters feel about different issues---on which that analysis was done.

That may sound like a small distinction, but it’s a crucial one. Ever since it burst onto the scene of American politics in 2015, Cambridge has trumpeted its massive data trove, boasting 5,000 data points on every American. Cambridge claims to have built extensive personality profiles on every American, which it uses for so-called “psychographic targeting,” based on people’s personality types. It is feared by some, including Hillary Clinton, for conducting a kind of psychological warfare against the American people and dismissed by others as snake oil. Both Parscale and Oczkowski have said repeatedly that the Trump campaign did not use psychographic targeting. Questions also have swirled about how Cambridge accumulated the data. Liberal voters in particular worried that their data had been harvested without their knowledge and used to elect Trump. But according to both Parscale and Oczkowski, the campaign didn’t use Cambridge’s trove of data, opting instead for the RNC’s data file.

“The RNC was the voter file of record for the campaign, but we were the intelligence on top of the voter file,” Oczkowski says. “Sometimes the sales pitch can be a bit inflated, and I think people can misconstrue that.”

Parscale describes the firm's work this way: "As I’ve said multiple times over prior statements, Matt Oczkowski and his team created a daily tracker of polling, so that I could see how Trump was doing in key swing states. They provided that to me daily." Parscale says Cambridge also helped the campaign with what he calls "persuasion online media buying. They also helped us identify potential donors. And they created a visualization tool that showed in each state which areas were most persuadable and what those voters care about.”

Cambridge Analytica was paid $5.9 million by the Trump campaign, according to Federal Election Commission filings, $5 million of which went toward buying television ads, with the remainder going to pay Oczkowski and his team. But that wasn't the only work Cambridge did for the campaign. Parscale says Cambridge’s head of digital, Molly Schweikert, managed an advertising budget of roughly $12 million on behalf of Parscale's firm, Giles-Parscale. It’s a sizable, but still small slice of the $94 million Giles-Parscale was paid in total to purchase the campaign’s ads.