• The fallout from President Trump’s abrupt firing of James Comey, the F.B.I. director, dominated a Senate hearing about the biggest security threats facing the United States.

Andrew McCabe, the acting F.B.I. director, rejected the White House’s claim that Mr. Comey had lost the support of his colleagues, and pledged to resist any attempt to hobble the investigation of Russia’s meddling in the 2016 presidential election.

We also learned that Mr. Trump had pressed Mr. Comey to promise loyalty to him at a private dinner in January, but Mr. Comey promised him only “honesty.”