U.S. Attorney General Jeff Sessions plans to meet with state attorneys general this month to discuss whether social media companies are stifling free expression, according to a statement released today.

The Justice Department raised the prospect of a possible investigation as Facebook COO Sheryl Sandberg and Twitter CEO Jack Dorsey concluded their testimony today before the Senate Intelligence Committee, where they addressed efforts to prevent foreign abuse of their platforms.

The Senate committee struck a calm bipartisan tone, as it spoke with the Silicon Valley executives about their efforts to thwart misinformation campaigns ahead of November’s midterm elections (and castigated Google for declining to participate). Meanwhile, President Donald Trump granted an interview with the conservative website The Daily Caller, in which he accused the social media sites of anti-conservative bias.

“The truth is they were all on Hillary Clinton’s side,” said Trump, who’s fond of reliving the 2016 campaign. “And if you look at what was going on with Facebook and with Google and all of it, they were very much on her side.”

Republicans have been amping up their criticism of social media in recent months, claiming these platforms stifle conservative voices. Facebook, in particular, has been grabbling with allegations of censorship since the tech site Gizmodo reported two years ago that the team in charge of the site’s “trending” list of stories was actively suppressing conservative news sources.

Facebook has vigorously and repeatedly denied charges of ideological bias, as recently as CEO Mark Zuckerberg’s testimony in April. The issue resurfaced anew, as Apple, Google’s YouTube, Facebook, Spotify and other platforms banned the right-wing conspiracy theorist Alex Jones.

Sen. Ted Cruz, Republican of Texas, tweeted in August, “Am no fan of Jones — among other things he has a habit of repeatedly slandering my Dad by falsely and absurdly accusing him of killing JFK — but who the hell made Facebook the arbiter of political speech?”

Perceptions of bias are widely held by Republicans. One Pew Research study from earlier this summer revealed that fully 85% of GOP and right-leaning independents think it is likely that social media sites intentionally censor political speech.

That set the backdrop for today’s hearing, which Justice Department spokesman Devin O’Malley said the DOJ monitored.

“The Attorney General has convened a meeting with a number of state attorneys general this month to discuss the growing concern that these companies may be hurting competition and intentionally stifling the free exchange of ideas,” O’Malley said in a statement.