President Trump is intensifying his efforts to undermine the nation’s intelligence agencies.

On Wednesday, Mr. Trump announced that he was replacing the acting director of national intelligence, Joseph Maguire, with Richard Grenell, the ambassador to Germany.

Mr. Maguire is a retired Navy admiral who previously served as the head of the National Counterterrorism Center. Mr. Trump tapped him to lead the Office of the Director of National Intelligence last August to replace the outgoing director, Dan Coats. Until recently, Mr. Maguire was thought to have a decent shot at becoming the permanent director of the office, overseeing the nation’s spy agencies.

But that was before one of his aides gave a classified briefing on Feb. 13 to the House Intelligence Committee, in which she warned that Russia was attempting to meddle in the 2020 election with an eye toward aiding Mr. Trump — as it had in 2016.

Mr. Trump doesn’t like to hear about election interference, much less about interference by Russia. He sees the entire topic as an effort to devalue his 2016 victory. Members of his administration, as well as congressional Republicans, know that this is a matter to be broached delicately, if at all.