Last week Facebook announced that fake accounts controlled by Russian operatives had purchased more than $100,000 in political ads on the site over the last two years. Just how serious are these revelations? On Tuesday, the ranking Democratic member of the Senate Intelligence Committee told reporters the committee was considering holding hearings about the revelations, with testimony from Facebook representatives.

Moreover, a report released Monday found that the same operatives who bought the ads used Facebook’s services to plan anti-immigrant rallies on U.S. soil, a troubling sign that Russian efforts to spread discord and disinformation in America went further than previously expected.

This is pretty serious. But despite voluntarily disclosing this information, Facebook has been less than forthcoming about the role it played, intentionally or not, in Russia’s campaign to influence American politics. Americans deserve accountability, but they’ve mostly gotten obfuscation from Facebook CEO Mark Zuckerberg.

The company’s abdication of any responsibility began just a few days after the election, when Zuckerberg callously downplayed the power of his own website.

“Personally, I think the idea that fake news on Facebook — it’s a very small amount of the content — influenced the election in any way is a pretty crazy idea,” he said on Nov. 10.

As late as last July, the company was still issuing denials like this one: “We have seen no evidence that Russian actors bought ads on Facebook in connection with the election.” Now, of course, the company has admitted to exactly that. Russian actors did buy ads on Facebook in connection with the election. Oops.

But even after their mea culpa, Facebook still refuses to be transparent. Despite growing pressure, they will not make public any of the ads bought by fake Russian accounts — nor share them with congressional investigators. They say they are protecting the privacy of their users, but the accounts that bought these ads were fabrications in the first place and have since been removed from the website.

It’s clear that Zuckerberg and his company are unwilling to reckon with their website’s profound influence on public discourse nor the real damage that can be done if that influence is compromised. Sixty-eight percent of U.S. adults use Facebook, and of those users, the Daily Beast reports that at least 23 million and as many as 70 million were exposed to the Russian-bought ads.

If Facebook won’t voluntarily come to terms with this and make changes, then it is in the public interest for the Senate Intelligence Committee to hold hearings and ask for testimony from the company’s executives — as well as representatives from Twitter, which also fell victim to fake Russian accounts. As Russian operatives wage a war of lies and misinformation, preserving the integrity of these broad avenues of communication has never been more important, and people like Zuckerberg should take their role as caretakers seriously.

Groves is a philosophy junior from Dallas.