The world's largest social media companies defended their decisions not to censor primary-source document publisher WikiLeaks, telling senators Wednesday the organization has done nothing that would justify being muzzled.

Sen. Tom Cotton, R-Ark., extracted corporate explanations after calling WikiLeaks a "non-state hostile intelligence service" at an open hearing of the Senate intelligence committee.

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Cotton asked Twitter CEO Jack Dorsey and Facebook Chief Operating Officer Sheryl Sandberg why they had not censored the document depot or its editor, Julian Assange, an Australian-born critic of U.S. foreign policy.

"Secretary of State Mike Pompeo, when he was director of the CIA, characterized WikiLeaks as a non-state hostile intelligence service. This committee has agreed with that assessment now for a couple years in a row," Cotton said.

"Yet WikiLeaks, which propagated some of the leaked emails in the 2016 election from the Democrats, remain[s] active on both Facebook and Twitter, as does Julian Assange," Cotton continued. "Ms. Sandberg, could you explain why Facebook continues to allow their accounts to be active?"

Sandberg said she was "not going to defend WikiLeaks ... [or] defend the actions of any page or actor on our platform," before proceeding to defend the company's decision against censorship.

"WikiLeaks has been public information. It's available broadly on other media and as such it doesn't violate our terms of service, and it remains up on our site," she said.

Dorsey added: "We also have not found any violation of our terms of service. But we are open as always to any law enforcement insight that would indicate a violation of our terms."

Cotton asked his question in the context of social media giants removing accounts believed to be associated with Russian attempts to influence the 2016 election. U.S. spy agencies say WikiLeaks — which previously released classified U.S. diplomatic and military documents — published emails hacked by Russia. Traditional news outlets also routinely publish classified information and worked with alleged Russian-controlled accounts to acquire and publish hacked emails.

Recently, social media companies have expelled or temporarily suspended controversial political figures, such as news commentator and conspiracy theorist Alex Jones, resulting in allegations of inappropriate "censorship" by President Trump.

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