This issue can only hurt McCain. People on the right are just fooling themselves, this could be a big problem. For the average person, they might not say it but they will feel uncomfortable putting her in the White House because of it. The Democrats should stay clear of it and let the media run with it.
If she were a Democrat or a known Republican it probably would be ignored but an unknown Republican who the media are looking to define, she better have one hell of speech at the convention.
McCain 48%
Obama 51%
Other 1%
McCain 272 EV
Obama 266 EV
House 266 Dems 169 Repub
Senate 56 Dems 52 Repub 2 Ind