According to former employees of Facebook, the world’s social media behemoth routinely downplayed conservative-sourced news whenever it started trending on the website. Millions of people turn to the site every day as a virtual watering hole, and it’s often the biggest driver of web traffic to news publications. In turn, that information affects Americans’ opinions about government and policy. To help facilitate the discussion, Facebook keeps a running sidebar of subjects that are trending on the site. In the past, people assumed Facebook’s algorithm dispassionately highlighted stories with the most buzz and writers would create snappy descriptions of the event or video or subject. But according to former curators, Facebook leaned on the scale when it came to what’s trending.

“I believe it had a chilling effect on conservative news,” one said. For example, stories about the late SEAL sniper Chris Kyle were ignored while on slow news days, the Facebook curation team would push out stories about the Black Lives Matter movement or incessant and pointless speculation on Malaysia Airlines flight MH370 — even as interest in those stories waned. And when a conservative news site broke a story, Facebook curators would marginalize their efforts by looking for Leftmedia news sites that wrote about the same topic.

In responding to these accusations, Facebook said a statement: “We take allegations of bias very seriously. Facebook is a platform for people and perspectives from across the political spectrum. … There are rigorous guidelines in place for the review team to ensure consistency and neutrality.”

So that would be a non-denial. But make no mistake: Facebook wields real power in politics. In March, more than a few Facebook employees wanted a discussion with founder Mark Zuckerberg about the company’s “responsibility” to stop Donald Trump’s candidacy. And if a down-to-the-wire election occurred like it did in 2000, Facebook could be a factor in boosting voter turnout — by using its algorithm to remind certain (read: pro-Hillary) voters to head to the polls. Or it could smother pro-Trump stories from the site. More important, how would we know Facebook is doing it?

> Update: The manager of this section of Facebook is a maximum donor to none other than Hillary Clinton.