Conservative politicians and pundits say tech companies are censoring them.

For the past couple of years, conservatives have said they're under attack online from the very services they use to communicate.

Now Capitol Hill lawmakers are holding their second hearing to discuss the issue. The Senate Judiciary Committee's Subcommittee on the Constitution has scheduled a hearing for Wednesday titled "Stifling Free Speech: Technological Censorship and the Public Discourse." 

A Facebook spokesperson said Neil Potts, the social network's public policy director, will be testifying. Twitter will send Carlos Monje, Jr., director of public policy and philanthropy for the US and Canada. Google had offered to send Max Pappas, the search giant's head of conservative outreach, but a source familiar with the situation said the committee rejected his appearance. 

The hearing marks the latest high-profile attempt to bring the topic of Silicon Valley's politics into a national conversation about tech and its many screwups over the past few years. For the most part attention has been focused on issues like election interference and privacy. But President Donald Trump and other conservatives have tried steering the debate to censorship, especially as companies like Facebook and Twitter have banned controversial figures like conspiracy theorist Alex Jones from their services.

"I will say there are a great many Americans who I think are deeply concerned that Facebook and other tech companies are engaged in a pervasive pattern of bias and political censorship," Sen. Ted Cruz of Texas said last year during a hearing with Facebook CEO Mark Zuckerberg.

Wednesday's hearing will mark the second such time tech executives will testify on Capitol Hill specifically to talk about censorship. Last year, the House Energy and Commerce Committee discussed censorship with Twitter CEO Jack Dorsey.

"How do we earn more trust from the people using our service?" Dorsey said at the time. "We know the way to earn more trust around how we make decisions on our platform is to be as transparent as possible."

While the Senate will be focused on censorship concerns, the House of Representatives is busy discussing the spread of online extremism.

On Tuesday, Facebook and Google representatives attended a hearing before the House Judiciary Committee that was prompted by last month's massacre in Christchurch, New Zealand, in which a terrorist attacked two mosques, killing 50 people. The gunman livestreamed the massacre on Facebook, prompting people to download copies and spread them across the internet. The video's spread, and Facebook's, Google's and Twitter's apparent inability to stop it, raised questions about what these companies are doing to prevent such content on their services.

The Judiciary Committee hearing was livestreamed on Google-owned YouTube, and hateful remarks flooded the comments section, pushing anti-Semitic views, criticizing multicultural societies and expressing white pride. Google ultimately shut down the ability to comment.

Here are the details about the Senate hearing:

Wednesday, April 10, at 11:30 a.m. PT (2:30 p.m. ET). 

It'll be livestreamed on the committee's webpage here and on Cruz's Facebook page. We'll also have the video playing on this page.

The hearing itself is set to take place in room 226 in the Dirksen Senate Office Building in Washington, DC.

Facebook and Twitter have been targeted by conservative groups and Trump for alleged censorship of right-wing voices. Trump in particular has threatened to "do something about" the "collusion" he believes is happening between tech companies. His concerns stem from "hatred they have for a certain group of people that happen to be in power, that happen to have won the election."

Cruz has raised these concerns as well during previous Senate hearings with tech executives. It's fair to expect he'll raise them again, and that meanwhile, Democrats on the committee will try to shift the conversation to discussion of extremism on the web, which was the topic of the House Judiciary Committee's Tuesday hearing.

For their part, the tech companies have said they don't unfairly target conservatives.

Still, Facebook in particular has also begun publicly advocating for more regulation of the tech industry. Last month Zuckerberg published an opinion piece in The Washington Post asking for more clearcut rules around extremist speech, among other things.

Originally published April 8, 12:31 p.m. PT.Update, April 10: Adds details about House hearing; and 11:21 a.m.: Adds details about Google not appearing at the hearing.

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