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Facebook Inc. and Twitter Inc. policy leads faced an onslaught of questions at a Senate Judiciary Committee hearing Wednesday over allegations their platforms disproportionately censor conservative speech.

Sen. Ted Cruz R-Texas has repeatedly raised concerns that social media platforms including Facebook, Twitter and Google show a "consistent pattern of political bias" in content moderation. He noted at the hearing's start that his allegations are based on "just a handful of anecdotes" but that those anecdotes "seem to be consistently on one side of the spectrum." Cruz said tech companies could conceal data showing bias.

On Wednesday, he proposed potential solutions to the alleged bias: remove platforms' liability protections under Section 230, break up big tech companies with stronger antitrust enforcement, or "under principles of fraud."

Carlos Monje Jr., Twitter's director of public policy and philanthropy for the U.S. and Canada, pushed back on Cruz's claims. He admitted the platform has made content moderation mistakes and apologized to committee member Sen. Marsha Blackburn, R-Tennessee, for Twitter's removal of her campaign ad last year.

But he claims Twitter's content moderation mishaps don't equal unfair censorship. The platform handles an estimated 500 million posts a day, he said, so "one in a million happens 500 times a day at Twitter."

"If you are looking for data points to support any narrative you can find it," Monje said. He added Twitter has removed posts from liberal and Democrat users, but declined to share specific names, though he said he could follow up with more specific moderation stats.

Neil Potts, the public policy director for Facebook who testified in front of Congress on Tuesday, denied that the platform censors conservative speech and also promised to follow up with clearer data on the political leanings of removed content. He said Facebook has a "rigorous program" to address bias and that moderators' political preference don't seep into their decisions at work.

"It seems to be mathematically impossible to suggest that there isn't some subjective judgment calling going on and that some of that might not be impacted by who works there," said Sen. Mike Lee, R-Utah.

Senators also raised concerns about censored Google results, but the Mountain View, California-based company did not have a representative present. Cruz denied Google's offer to send Max Pappas, its acting director of political and stakeholder outreach who is also Cruz's former director of outreach.

In September, the Senate Intelligence Committee rejected Google head of legal Kent Walker as a witness for a hearing on election interference, requesting a more senior official be sent. Later that month, a video emerged of Walker and other Google executives expressing shock over the results of the 2016 election, fueling concerns of political bias on the platform.

A Google spokesperson said in a September statement that "nothing was said at that meeting ... to suggest that any political bias ever influences the way we build or operate our products."

Sen. Mazie Hirono, D-Hawaii, said Wednesday that Pappas should have been permitted to testify because he is at "the same level of responsibility as our two witnesses right now."

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