(Bloomberg) -- President Donald Trump is keeping up pressure on social media giants even in the waning days of his administration.Trump on Tuesday night threatened to veto a defense bill if it doesn’t take aim at a liability shield enjoyed by the social media platforms, while on Wednesday the Senate advanced his nominee who favors weakening that shield to the Federal Communications Commission.The developments ensure more struggles over the provision known as Section 230 that protects technology companies such as Twitter Inc. and Facebook Inc. from liability over most content published by their users. Trump has accused the companies of discriminating against his views.“Repealing Section 230 is itself a threat to national security,” Jon Berroya, interim president of the Internet Association trade group representing online companies, said in a statement. “The law empowers online platforms to remove harmful and dangerous content, including terrorist content and misinformation. Section 230 also underpins countless e-commerce websites, apps, and services.”Leaders of both parties rebuffed Trump’s demands on the defense bill on Wednesday by announcing an agreement on the measure and said the legislation didn’t address social media, despite the threatened veto.“First of all, 230 has nothing to do with the military,” Senator James Inhofe, the Oklahoma Republican who is chairman of the Armed Services Committee, told reporters. “I agree with his sentiments, we ought to do away with 230. But you can’t do it in this bill.”Inhofe said he had spoken with Senate Majority Leader Mitch McConnell and expected the defense measure to get a floor vote next week.Representative Adam Smith, of Washington, the Democratic chairman of the House Armed Services Committee, in a tweet directed at Trump said the president was “willing to veto the defense bill over something that has everything to do with your ego, and nothing to do with defense.”At the same time, the Senate Commerce Committee’s Republicans advanced the FCC nomination of Nathan Simington, an administration official who helped write Trump’s proposed rule to increase social media’s exposure to lawsuits. The committee voted 14-12 along party-lines.The rule, pending at the FCC, would weaken defenses against litigation over removing or labeling user posts. Trump proposed the measure after Twitter began selective fact checks of his tweets. The president and his allies have said with scant evidence that popular platforms discriminate against conservative voices.In the Senate Commerce Committee, Connecticut Democrat Richard Blumenthal said he would seek to block Simington’s nomination from a vote on the Senate floor.“It would seem that Mr. Simington is nominated for just one purpose: to support the president’s indefensible assault on the First Amendment,” Blumenthal said.If Simington’s confirmed, he would be in the FCC majority through Inauguration Day Jan. 20, then part of a 2-to-2 deadlock that could last months until the Senate confirms a Biden addition to the agency.FCC Chairman Ajit Pai, a Trump appointee, has said he will advance the Section 230 rulemaking that Simington helped to write. Pai hasn’t laid out his plans in detail and time is tight to do so.Pai would need to follow “extraordinary” procedures to adopt the matter by the time he leaves on Jan. 20, and whatever emerges would be vulnerable to reversal as Democrats take over the agency, said Andrew Jay Schwartzman of the Benton Institute for Broadband & Society.If FCC Democrats have a majority, they could simply rescind the last-minute action. Even if the agency is in a partisan tie, the FCC could refuse to defend Pai’s action against a likely legal challenge. Once the partisan tie is broken when a Biden nominee arrives, the agency could take up requests to reconsider and revoke the action, Schwartzman said in an interview.Brian Hart, an FCC spokesman, didn’t respond to telephone and email queries about Pai’s intentions.(Updates with lawmakers rebuffing Trump, beginning in fifth paragraph)For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.©2020 Bloomberg L.P.