Mr. Nunes singled out Liz Mair, a Republican strategist who said on Twitter that she would not comment on the lawsuit, and two parody accounts: @DevinNunesMom, which was suspended last year, and @DevinCow, which is still active. The complaint says that Ms. Mair coordinated with the anonymous accounts on “a vicious defamation campaign” but did not offer evidence she was behind them or communicated with them, except for one tweet encouraging people to follow @DevinCow.

Experts generally say the law protects large internet platforms like Twitter, Facebook and YouTube from liability based on what their users publish. Section 230 of the Communications Decency Act says they should not “be treated as the publisher or speaker” of the content — allowing the platforms to exist without having to preapprove every post for potential legal issues.

But the complaint by Mr. Nunes seeks to portray the tweets directed at him as evidence of larger efforts by Twitter to undermine Republicans — a frequent rallying cry of conservatives. Mr. Nunes was a key figure in the House’s Russia investigation, and a frequent target for critics who said he was abusing his authority by impeding investigations to protect Mr. Trump.

“As part of its agenda to squelch Nunes’ voice, cause him extreme pain and suffering, influence the 2018 Congressional election, and distract, intimidate and interfere with Nunes’ investigation into corruption and Russian involvement in the 2016 Presidential Election, Twitter did absolutely nothing,” the complaint said.

Twitter declined to comment on the lawsuit. But in public statements, including contentious House committee hearings in September, executives have denied any political bias or agendas. Jack Dorsey, the chief executive of Twitter, told the House committee they had found no difference in the reach of tweets by Democrats and those by Republicans.