FBI Director James Comey appears Wednesday before the House Judiciary Committee, where he’ll get another chance to explain his agency’s double standard regarding Hillary Clinton. His probe of the former Secretary of State’s private email server is looking more like a kid-glove exercise with each new revelation.

House Oversight Chairman Jason Chaffetz on Friday disclosed that the FBI granted immunity to Mrs. Clinton’s top aides as part of its probe into whether Mrs. Clinton mishandled classified information. According to Mr....