No. Her poll numbers were falling before that, and at the absolute most Wisconsin and Michigan might've stayed D. The overwhelming majority of voters had already made up their minds before the Comey letter and probably anyone who used that as an excuse not to vote for her wasn't planning on doing so anyway and would've cited something else instead.
PA was about as close as WI was, though. If WI flips, doesn't PA also have a decent chance of flipping?
BTW, the race might have gone into the House of Representatives had Trump held PA but lost MI and WI. It all depends on those two Trump electors that went rogue in real life.
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