President Trump’s re-election campaign sued The New York Times for libel on Wednesday, alleging that an Op-Ed article published by the newspaper falsely asserted a “quid pro quo” between Russian officials and Mr. Trump’s 2016 campaign.

Mr. Trump often threatens to sue media organizations but rarely follows through. The lawsuit, filed in New York State court in Manhattan, is the first time his political operation has taken legal action against an American news outlet since he took office.