Why would McCain put out an ad featuring Obama, in which Obama claims that McCain is lying? Note that it doesn't refute Obama; it just shows Obama saying that McCain is lying. Which is what Obama believes and says.
Does this really help McCain?
By the way, I have yet to see a McCain ad here in North Carolina. And the Obama ads are very well tailored to this region. One of them starts off by saying that Obama supports the Second Amendment (which is true).
And then there is this: