Why FBI Director Made Clinton Email Announcement Now

Democratic presidential nominee Hillary Clinton listens as her rival, Republican candidate Donald Trump speaks, during their third and final debate at the University of Nevada, Las Vegas on October 19. The FBI says it will investigate newly discovered emails related to Clinton’s use of a private server while secretary of state. Joe Raedle/Reuters

Updated | Why did FBI Director James Comey shock Washington on Friday with an announcement that the FBI "has learned of the existence of emails" related to Hillary Clinton's private email server, and what does it mean?

The truth is Comey didn't have a choice. Because the new information followed his sworn testimony about the case, Comey was obligated by Department of Justice rules to keep the relevant committees apprised.

Under oath Comey had stated that the bureau had completed its review. Once he learned that there were new emails that required examination, Comey had to notify Congress that he had to amend his testimony because it was no longer true.

Comey's letter to congressional committee chairs doesn't say his agents have discovered new witnesses or documents suggesting a criminal act occurred. Rather, he only suggests that evidence that has not yet been examined needs to be reviewed because it is relevant to the case.

There's also a political dimension. Had Comey not told Congress and it emerged after the election that new materials had come into its possession, the director and his entire agency's credibility might have been questioned.

In his letter, Comey did not use the phrase being touted by Republicans that the case had been reopened. Technically it was never closed. Nor did he signal at all about the importance or unimportance about the emails.

"In connection with an unrelated case, the FBI has learned of the existence of emails that appear to be pertinent to the investigation," he said in his letter to the chairs. "Although the FBI cannot yet assess whether or not this material may be significant, and I cannot predict how long it will take us to complete this additional work, I believe it is important to update you."

On the other hand, Comey did not offer any indication from whence the new evidence comes. By his omission he's left a country in suspense. Later in the day, news reports, unconfirmed by Newsweek, indicated that the emails were found in the course of an investigation of Anthony Weiner, the former New York congressman who is married to Clinton aide Huma Abedin, and that they were found on a device of Weiner's. He and Abedin announced a marital separation this summer after he was revealed to be exchanging lewd photos and emails with women, one of whom was reportedly underaged.

Republicans were jubilant on Friday, seeing the Comey letter as something that could save the flailing Donald Trump campaign for president. The GOP nominee himself heaped praise on the FBI director after castigating him since his summer announcement that the bureau had not recommended a criminal charge be brought against Clinton.

"I have great respect for the fact that the FBI and the Department of Justice are now willing to have the courage to right the horrible mistake that they made," Trump said at a rally in New Hampshire early Friday afternoon. "This was a grave miscarriage of justice that the American people fully understood. And it is everybody's hope that it is about to be corrected."

House Speaker Paul Ryan called for an end to Clinton receiving classified briefings.

Clinton's campaign chairman, John Podesta, called on Comey to immediately release more details about the new evidence. Campaigning in Iowa, Clinton read a brief statement before a group of reporters and answered a couple of questions. She did not answer a question about whether she had discussed the matter with Abedin. The Democratic nominee echoed Podesta's call for Comey to release more information: "Let's get it out." Clinton laughed when she a reporter asked her if Comey's letter would "sink" the campaign.

This article has been updated to indicate that news reports say the Clinton emails were uncovered during the investigation of Anthony Weiner and that Podesta has pushed back against Comey.