We’ve known since at least 2012 that Facebook was a powerful, non-neutral force in electoral politics. In that year, a combined University of California, San Diego and Facebook research team led by James Fowler published a study in Nature, which argued that Facebook’s “I Voted” button had driven a small but measurable increase in turnout, primarily among young people.

Rebecca Rosen’s 2012 story, “Did Facebook Give Democrats the Upper Hand?” relied on new research from Fowler, et al., about the presidential election that year. Again, the conclusion of their work was that Facebook’s get-out-the-vote message could have driven a substantial chunk of the increase in youth voter participation in the 2012 general election. Fowler told Rosen that it was “even possible that Facebook is completely responsible” for the youth voter increase. And because a higher proportion of young people vote Democratic than the general population, the net effect of Facebook’s GOTV effort would have been to help the Dems.

The research showed that a small design change by Facebook could have electoral repercussions, especially with America’s electoral-college format in which a few hotly contested states have a disproportionate impact on the national outcome. And the pro-liberal effect it implied became enshrined as an axiom of how campaign staffers, reporters, and academics viewed social media.