I really don’t think it will be that effective. The MSM will spin the release of this info as something sinister and fabricated. They can claim the Russians tampered with the emails or created them out of thin air. They will claim that it is an attempt by our enemy to prevent a strong leader like Hillary from becoming President. Never underestimate the power of MSM.
I have no doubt they will spin it that way for sure, but it only has to really resonate with a percentage to be effective. I think it would cause the Democrats much consternation though, even if they do not show it outright.