Plusses and minuses on the "tightening race" narrative
Plus for Dems:
should help keep people motivated to get out to vote, interested in outcome
Negatives for Dems:
Looks like Trump has momentum
Give Rs a reason to get out to vote
If it ends up that the tightness was fake, and Hillary wins by a lot, then will cause R's to think she rigged it
If she wins after it being so tight, it will cause R's to think she rigged it
Neutral for Dems:
Drives more attention to election coverage, helps media
Bottom line
A slight net negative for Dems unless the Dems can really capitalize on the increased interest in the race and hammer home their argument.
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Did I miss anything key?
I tend to think there's SOME tightening, with GOPers coming back to Trump, but I find it hard to believe the dynamic of the race has changed that much, with HRC the overall favorite.