All of a sudden Hillary Clinton and her presidential campaign have discovered the virtues of transparency. And all of a sudden FBI Director James Comey, formerly Eliot Ness in the eyes of Democrats and the press, is J. Edgar Hoover. Such are the miraculous political transformations caused by Mr. Comey’s announcement Friday that the FBI has found more emails that may be relevant to Mrs. Clinton’s mishandling of classified information.

“It’s not just strange. It’s unprecedented, and it is deeply troubling, because voters deserve to get full and complete facts,” Mrs. Clinton said Saturday about Mr. Comey’s letter to Congress. That wasn’t her line when she created her personal email server to hide her correspondence from public-records laws, or when she claimed not to have sent classified information or did as little as possible to cooperate with Congress and the FBI.

Mrs. Clinton could still help voters out by coughing up her 33,000 missing emails. Or she could let her aide Huma Abedin explain to the press what she may have sent to estranged husband Anthony Weiner, whose laptop contains the new-found emails. But that kind of genuine transparency might be hard to contain. And with eight days until Nov. 8 the Democrats need someone else to blame for all of their previous lack of political transparency.

That means Mr. Comey, who over the weekend became the latest stand-in for the vast right-wing conspiracy. “By providing selective information, he has allowed partisans to distort and exaggerate in order to inflict maximum political damage, and no one can separate what is true from what is not because Comey has not been forthcoming with the facts,” said a clearly agitated Clinton campaign chief John Podesta in a media call Saturday.

Look for more to come as Democrats attempt to mobilize their supporters to vote by turning Mr. Comey into Whitewater prosecutor Ken Starr. This won’t be easy since Mr. Comey was appointed by President Obama, and Democrats have spent so many years praising Mr. Comey as St. James of the Beltway.