Mark Zuckerberg is trying hard to convince voters that Facebook had no nefarious role in this election. But according to President-elect Donald Trump's digital director Brad Parscale, the social media giant was massively influential—not because it was tipping the scales with fake news, but because it helped generate the bulk of the campaign's $250 million in online fundraising.

"Our biggest incubator that allowed us to generate that money was Facebook," says Parscale, who has been working for the campaign since before Trump officially announced his candidacy a year and a half ago. Over the course of the election cycle, Trump's campaign funneled $90 million to Parscale's San Antonio-based firm, most of which went toward digital advertising. And Parscale says more of that ad money went to Facebook than to any other platform.

'Facebook and Twitter were the reason we won this thing.' Brad Parscale

"Facebook and Twitter were the reason we won this thing," he says. "Twitter for Mr. Trump. And Facebook for fundraising."

In the wake of Trump's stunning upset last week, media analysts have worked feverishly to figure out how social media may have altered the outcome of this election. They—and we—have pointed to online echo chambers and the proliferation of fake news as the building blocks of Trump's victory. But the answer may be much simpler. Of course Facebook was hugely influential in the presidential election, in large part because Trump's campaign embraced Facebook as a key advertising channel in a way that no presidential campaign has before—not even Clinton's.

"I think the Trump campaign did that extremely well," says Andrew Bleeker, president of Bully Pulpit Interactive, which helped lead Hillary Clinton's digital marketing efforts. "They spent a higher percentage of their spending on digital than we did."

Changing Minds Where It Mattered

Throughout the last year-and-a-half, stories about the imbalance between Clinton's ad spending compared to Trump's proliferated. They noted how Clinton spent more than $200 million on television ads in the final months of the election while Trump spent less than half that. Because Trump wasn’t spending as much on television all along, it seemed like his team wasn't investing in changing anyone’s minds. But they were: they were just doing it online.

"The big takeaway was using digital in a digital-first way," says Matt Lira, a Republican digital strategist and senior advisor to House Majority Leader Kevin McCarthy. "It was the main course. It wasn't leftovers."

Facebook proved to be a powerful way for Trump's team to hone the campaign's message with the kind of enormous sample sizes you can't get with traditional polling. "They have an advantage of a platform that has users that are conditioned to click and engage and give you feedback," says Gary Coby, director of advertising at the Republican National Committee, who worked on Trump's campaign. "Their platform’s built to inform you about what people like and dislike."

Coby's team took full advantage of the ability to perform massive tests with its ads. On any given day, Coby says, the campaign was running 40,000 to 50,000 variants of its ads, testing how they performed in different formats, with subtitles and without, and static versus video, among other small differences. On the day of the third presidential debate in October, the team ran 175,000 variations. Coby calls this approach "A/B testing on steroids." The more variations the team was able to produce, Coby says, the higher the likelihood that its ads would actually be served to Facebook users.

"Every ad network and platform wants to serve the ad that's going to get the most engagement," Coby says. "The more you're testing, the more opportunity you have to find the best setup."

The Digital Bully Pulpit

Clinton also had a robust digital strategy, investing $30 million in digital ads in the homestretch. Her campaign produced thousands of rapid-response videos and set up a customer service team to help people with their voting questions. But, says Bleeker, "the Trump campaign took to an extreme what we were trying to do on the Hillary campaign."

The President-elect has shown he can turn a news cycle in 140 characters or less.

Social media was Trump's primary communication channel. It wasn't a platform for broadcasting pre-planned messages but for interacting with supporters and starting new conversations—however controversial those conversations often were. Bleeker says one of the biggest lessons he's learned from this election cycle is that social media is increasingly going to be part of any candidate's so-called "earned media strategy"—that is, the coverage a candidate gets for free in the press. The President-elect has shown he can turn a news cycle in 140 characters or less; in a recent 60 Minutes interview, he said he plans to continue using Twitter as president.

"He’s going to tell his side of the story from the digital bully pulpit," Lira says.

Whether fake news did or didn't affect the election's outcome, Facebook as a platform did. The winning candidate was not just willing, but eager to break with traditional models of campaigning. His team invested in new ways of using the digital tools and platforms that have come to dominate the media landscape. Anyone who wants to defeat him in the future will have to do the same.