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Two senior Democrats in Congress are demanding that Facebook and Twitter investigate whether Russian trolls and bots once again have tried to “manipulate public opinion” on their sites.

The concern for Sen. Dianne Feinstein and Rep. Adam Schiff, detailed in a new letter Tuesday, is the so-called #ReleasetheMemo campaign on social media. For weeks, Republicans have sought to call attention to a secret dossier they compiled that details abuses of power at the FBI — an effort that Democrats say is merely an attempt to discredit an investigation into Russian interference during the 2016 presidential election.

Nevertheless, the hashtag has reverberated widely on Facebook and Twitter, driven in no small part by tweets from the president’s own son. Adding to its popularity, however, appear to be Russian bots, according to researchers who study disinformation on social media.

To that end, Feinstein and Schiff have called on Facebook and Twitter to study their sites to determine how many accounts are involved in the campaign. The lawmakers have asked the companies to detail how many users might have seen posts and tweets amplified by Kremlin-aligned trolls.

“These recent Russian efforts are intended to influence congressional action and undermine Special Counsel Mueller’s investigation,” they wrote, noting that the probe “has already resulted in the indictments of two Trump campaign officials and guilty pleas from two others, who are both now cooperating with prosecutors.”

“It is critically important that the Special Counsel’s investigation be allowed to proceed without interference from inside or outside the United States,” the Democrats continued. “That is why we seek your assistance in our efforts to counter Russia’s continuing efforts to manipulate public opinion and undermine American democracy and the rule of law.”

Feinstein is the top Democrat on the Senate Judiciary Committee, while Schiff is his party’s leading member on the House Intelligence Committee. Both of their panels have probed Russian interference during the 2016 election — and they grilled representatives from Facebook, Google and Twitter on the matter last year.

All three companies admitted during those hearings that they had fallen victim to Russian trolls, including the Kremlin-supported Internet Research Agency. Posts and content generated by those foreign agents reached more than 126 million U.S. users on Facebook, the company said at the time. And similar messages — sowing social and political unrest — were amplified by tens of thousands of bots on Twitter, the company recently said.

In response, Facebook, Google and Twitter committed to Congress that they would keep closer watch over their platforms, while introducing new requirements targeting political ads that appear on their sites — hoping to stymie Russian agents from trying to influence U.S. politics again.

But the concern then — and now, in 2018 — is whether seemingly run-of-the-mill posts, photos and other forms of organic content are easily manipulated by Kremlin trolls.

“If these reports are accurate, we are witnessing an ongoing attack by the Russian government through Kremlin-linked social media actors directly acting to intervene and influence our democratic process,” wrote Feinstein and Schiff. “This should be disconcerting to all Americans, but especially your companies as, once again, it appears the vast majority of their efforts are concentrated on your platforms.”

Facebook and Twitter did not immediately respond Tuesday to emails seeking comment. They have until Jan. 26 to reply.

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