I don't know how much of an impact this is having on public opinion, but it's at least a small impact. I agree with PBeavr that people who have their minds set in either extreme aren't going to change their minds regardless of proof or the absence of it, and it's the undecided voter who will make the difference in such a close race. Whether this will impact the people's vote enough to make a difference in the election, though, is difficult to tell.
