Now we learn about the multiple immunity deals. Immunity in exchange for information that will help make the case against higher-ups is not unusual. Even so, the Mills deal carries a special stink.

To begin with, Ms. Mills was pretty high up herself. As Mrs. Clinton’s chief of staff, she was in the thick of operations. In 2012, while working at State, she traveled to New York to interview candidates for a top job at the Clinton Foundation.

More disturbing still, not only was Ms. Mills granted immunity for the content on her laptop, she was permitted to act as Mrs. Clinton’s attorney even though she herself was also a witness in the investigation.

This was allowed in part because she told the FBI she knew nothing of Mrs. Clinton’s private server until after she’d left the State Department. But this claim is suspect and contradicted by emails that have since emerged. These include one to Huma Abedin asking, “hrc email coming back—is server ok?”