Facebook, Twitter and Google testified in front of a Senate Judiciary subcommittee today about the extent to which Russian operatives used these powerful technology platforms to interfere with the 2016 election and foment division and discord — prompting more than one senator to suggest the need for government regulation.

The social media manipulation went beyond initial reports — with some 126 million Facebook users having been exposed to content produced and circulated by Russian propagandists. The company’s initial estimates were in the range of 10 million.

“When it comes to the 2016 election, I want to be clear: The foreign interference we saw is reprehensible and outrageous and opened a new battleground for our company, our industry and our society,” said Facebook general counsel Colin Stretch in testimony before the Senate Judiciary Committee’s Crime and Terrorism subcommittee. “That foreign actors, hiding behind fake accounts, abused our platform and our Internet services to try to sow division and discord — and to try to undermine our election process — is an assault on democracy, and it violates all of our values.”

Attorneys for Facebook and fellow Silicon Valley titans Google and Twitter sought to emphasize their commitment to preventing this from ever happening again. Facebook said it has made “significant investments” in artificial intelligence and implemented a more rigorous ad review process and tighter content controls to thwart bad actors and derail their malicious activities.

But these efforts at self-regulation might not be enough to appease anxious legislators, who over the course of the two-hour meeting expressed concerns about the power of these platforms.

Senator Amy Klobuchar
Klobuchar
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Sen. Amy Klobuchar (D-MN) said online political advertising should be subject to the same disclosure rules as campaign ads that appear on television, radio and in newspapers. She and Virginia Democratic Sen. Mark Warner are seeking to drum up support for a bill that would make Facebook and others disclose more information about who is buying political ads on social media platforms.

“There are no rules in place to tell us where these paid ads are coming from,” Klobuchar said during Tuesday’s hearing. “I do appreciate the efforts from these companies. I don’t think it’s enough.”

Anxiety over Russia’s attempts to meddle in the election — and subsequent efforts to amplify divisions over such contentious issues as immigration, gun ownership and the Black Lives Matter movement — served to underscore broader concerns about the clout of the social media platforms.

Texas GOP Sen. Ted Cruz talked about the outsized role social networks play in the nation’s political life and how an increasing percentage of Americans get their news online. He cited one 2013 study that explored Google’s theoretical ability to tilt elections or Twitter’s decision to block a Senate campaign ad from U.S. Rep. Marsha Blackburn because it included an anti-abortion reference to the “sale of baby body parts.”

“The prospect of Silicon Valley companies actively censoring speech or the news content is troubling to anyone who cares about the democratic process, with a robust First Amendment,” said the 2016 presidential candidate.

Twitter general counsel Sean Edgett defended the company’s belief in its role as an open forum for ideas. “Free speech is core to everything we do,” he said.

Senator Patrick Leahy
Sen. Patrick Leahy
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Sen. Richard Blumenthal, a Democrat from Connecticut, said he joined in support of Klobuchar’s bill to regulate political ads in the wake of Russia’s online misinformation campaign, which he called “a cancer on our democracy that will metastasize into distortions of our democratic process unless we throttle them by disclosure.”

Blumenthal was especially troubled by voter-suppression efforts on Twitter, one of which featured the image of actor-comedian Aziz Ansari and encouraged people to “save time and vote online” via text.

Twitter said it permanently suspended 106 accounts that were responsible for 734 “vote by text” tweets. But Twitter users were vigilant, with 10 times as many users refuting the misinformation, said Edgett.

Sen. Al Franken (D-MN) wondered aloud what took the data wizards of Silicon Valley so long to identify the Russian connection.

“Why didn’t anyone catch on earlier?” he asked. “How does Facebook, which prides itself on being able to process billions of data points … not make the connection that electoral ads paid for in rbbles were coming from Russia?”