It’s fitting that William Barr’s confirmation as attorney general happened just as two powerful law-enforcement figures were trading accusations involving President Trump. Barr’s greatest challenge isn’t antitrust deals, immigration policy or even handling special counsel Robert Mueller. His overriding challenge is to reboot a Justice Department that has shredded its reputation and lost the confidence of Congress and the public.

It’s hard to feel confident in law enforcement when a former deputy director of the Federal Bureau of Investigation, Andrew McCabe, reveals that a small cabal of unelected senior law-enforcement officers held meetings in May 2017 to plot Trump’s removal from office. In an interview with “60 Minutes” that aired Thursday and a forthcoming book, McCabe says he and other officials, including Deputy Attorney General Rod Rosenstein, did head-counts of which cabinet officials might vote to declare the president “unable to discharge the powers and duties of his office” under the 25th Amendment. McCabe claims Mr. Rosenstein repeatedly offered to wear a wire when meeting with Trump.