As leaked audio shows Mark Zuckerberg worrying about Sen. Elizabeth Warren, the site’s “I Voted” button could help tip the election for the president or another candidate.

Joshua Roberts / Reuters

The news Tuesday that Mark Zuckerberg is preparing to fight Sen. Elizabeth Warren's policies has returned the spotlight to an uncomfortable fact about Facebook’s scale and power: Its actions could help determine whether Warren, Donald Trump, or someone else is sworn into office in January 2021.

Facebook’s power to promote or block stories, lies, and personalities has been a central story over the last four years. But its greatest proven power in elections is more concrete: Facebook has shown that it can, with a campaign inside the service, drive its users to the polls. That’s because while Facebook’s cheerful, and scientifically proven, “I Voted” button seems neutral, it isn’t turning out a cross section of Americans. It’s turning out a cross section of people who use Facebook. And as Facebook’s user base morphs into the Trump coalition — older, less-educated, and more Republican — the platform's get-out-the-vote efforts could become a powerful element of the president's reelection campaign, one that could tip the vote in battleground states in the general election.

"You cannot participate in politics one way or the other without making a political statement."

“You cannot participate in politics one way or the other without making a political statement,” said Harper Reed, the chief technology officer for Obama's 2012 presidential campaign. A Facebook spokesperson declined to comment on whether the platform would run a get-out-the-vote campaign targeting its users in 2020 or to disclose the volume of any planned campaign. The spokesperson, who declined to be named, said, “Facebook provides people with accurate and nonpartisan information about how to register and participate in upcoming elections as part of our defenses against interference from bad actors.” Facebook’s role in the 2020 election has come under fire from Democrats recently. After the site’s vice president of global affairs, Nick Clegg, reaffirmed that politicians like Trump would not be subject to its fact-checking policies, Democratic National Committee CEO Seema Nanda claimed on CNN on Tuesday that the company is allowing Trump "to mislead the American people on their platform unimpeded." But little attention has focused on its neutral-seeming get-out-the-vote plans, which could prove consequential. There’s been no comprehensive survey of the political alignment of the site’s user base since 2015. The company has declined to share the data that would help settle this question, even though it has categorized its users as liberal, moderate, and conservative in the past. What is clear is that button has been a proven factor in driving people to the polls — a 2012 study published in the journal Nature found it increased turnout by 0.4%. Nevertheless, it’s becoming clear that Facebook’s profile increasingly matches the demographics of the Trump coalition. Since the 2016 election, the platform has shed millions of users in the United States, according to Edison Research, most pronounced among young people and millennials. And the share of older Americans using the site has grown. According to Pew Research, since 2012 use of Facebook has grown most rapidly among older generations. (Facebook’s aging matches the electorate — Pew expects nearly a quarter of voters in 2020 to be over 65, the highest share in 50 years.) Not only have older Americans increased proportionally on the site since 2016, their demographic is the one mostly likely to share things on it — things like the site’s “I Voted” button. So as Facebook mulls whether to push voters to the polls this election season, as it has done in several US presidential races and in elections around the world, could its voter button tilt the election toward Donald Trump?

"It’s different now, and that difference is 2016."