In the trench war between congressional Republicans and the Federal Bureau of Investigation, we have arrived at a crucial battle. A House resolution sets Friday as the deadline for the Justice Department to come clean on the beginning of its investigation into the Trump campaign. We’ll find out if the FBI has been lying to the public.

That is, if the department complies. It has flouted so many subpoenas, and played so many games with redactions and deadlines, that the entire House GOP united last week to vote for the resolution...