Mr. Comey must be pretty sure of himself -- and of the evidence he has -- to do something like this so late in the campaign.
Of course, hillary isn't going to be indicted before November 8, but that's not the intent.
The intent is to damage her enough that Trump gains the few percentage points in the battleground states he needs to get over 270 votes in the Electoral College and win.
The risks for Comey are great if his strategy fails.
If hillary wins, she'll go after him with everything she's got.
Why would he do this, facing such a risk?
Perhaps he believes he can salvage his reputation, which wasn't doing so well up to today. For all those who accused him of being corrupt or knuckling under to pressure from above, this is Mr. Comey's answer, and it's a good one.
He certainly would be out of his job come January 20 if hillary wins.
One can only conclude that Mr. Comey doesn't want her to win, and is doing his part to help Mr. Trump prevent that...