"I'll tell you this: Hillary's not distracted. Hillary's faced challenges before. She's not distracted," Kaine said at an election rally in Michigan, adding that the latest FBI move has increased the enthusiasm in the Clinton Campaign and her supporters.
"I'll tell you one thing this letter has done. We were chatting about this backstage. It has kind of revved up some enthusiasm, a little bit of - a little bit of righteous indignation and righteous anger. It's revved it up," he said.
Kaine called on the FBI to release details of its investigation.
"Look, now that you've thrown this kind of question mark letter out and already had to backtrack, you ought to put all the details out for the American public to see instead of doing this kind of big question mark right before the election. That's what we're asking be done," he said.
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Kaine said he and many like him "were surprised, stunned, puzzled, last week" when the FBI put out a letter on Friday, months after an expensive, massive investigation into the email question, and saying that no reasonable prosecutor would take any additional step, after reaching the conclusion.
"A month after doing that, his letter comes out Friday that doesn't really say- Donald Trump says, 'Oh, they're reopening the investigation.'"
Kaine said the letter was so confusing that it was hard to know exactly what it said. "And within 24 hours, Director Comey had to go back and kind of write a do-over letter," he said.
"None of the emails in question are emails that he's seen. He doesn't even know if they're to or from Hillary Clinton or to or from their private server.
"So I'm going to ask you this: Are any of you going to be distracted? Are any of you going to take your eye off the job at hand, which is produce an engaged electorate that will turn out and make the pick that we have to make in terms of our nation's next leadership? Nobody's going to be distracted," Kaine said.