Another shocker, and James Comey's signature is again at the bottom of it. The FBI Director wrote a letter to members of Congress, in which he states: "Based on our review, we have not changed our conclusions that we expressed in July with respect to Secretary Clinton."

That review was of Hillary Clinton's emails, and that conclusion then was her conduct was extremely careless, not criminal.

This time, add former Congressman Anthony Weiner to the mix. Agents came across the emails looking into his alleged online sexual messages with a teenager. Weiner's estranged wife is Huma Abedin, a top Clinton aide.

The letter rattled Clinton's campaign, just as her campaign seemed poised for a soft landing.

"It is pretty strange to put something like that out with so little information without an election," Clinton said. "In fact, it's not just strange, it's unprecedented - and it is deeply troubling."

Clinton didn't speak about the developments during a final appearance in Cleveland - with the basketball star Lebron James.

There seemed no need to draw more attention to an issue that has given her a political migraine.

 “When the letter came out two Fridays ago, it was obviously kind of a curve ball," Democratic VP candidate Tim Kaine said. "It sounds like the FBI conclusion is as we thought it would be.”

The precise effect of the FBI inquiry on the state of the presidential race may never be fully known. Polls tend to narrow at the end of contests.

The gap did narrow between Clinton and Trump - especially in the days after Comey's October 28th letter.

The average gap was more than four and a half percentage points then, and is less than two now.

It wasn't just the presidential race that was affected. It jeopardized Democrats once promising bid to retake the U.S. Senate. 

"I was appalled by what Director Comey did," Senator Charles Schumer said.

How the race is affected may never been known. It can take several days for public opinion to adjust to developments like these, and there aren't several days left. Also, upwards of 30 million people have already voted.