Not nearly as much as one would think. Time and again major stories and scandals have failed to penetrate, especially once he gets into details and he said/she said. Thus we need to continue to bust our butts explaining this story at the water cooler, social gatherings, etc.
Then along came the left, led by Howie Dean, to proclaim the EEEEVEEEEELS of Rush Limbaugh and his vast, conservative talk radio conspiracy and the Republican controlled media (that would include CNN) and swing voters became what OTHER information was available. IMO, it caused them to turn on Rush out of curiosity and surf the web for news more. Hannity already had a diverse ideological listener base because of Fox's H&C.
Even without all that we're talking about easily SEVERAL million people, Vietnamese refugees, Vietnam veterans and their families, who were directly or indirectly injured by Kerry's VVAW antics. Kerry reopening those wounds was a baaaaaaaad idea....for Kerry. The word is getting out.