The VP Debate: Too Bad Dick Cheney's Best Line Was A Lie
On this point, that helps Edwards. I doubt that voters care whether Edwards was present at the Senate while campaigning -- this is not a frame that has any traction. Cheney was smarter when he went more generally after Edwards's lack of experience and he should have hammered that more. Cheney's false statement about meeting Edwards directly plays into a worry that people already have about Cheney -- that he may be dishonest -- and connections to a general concern by voters that Bush and Cheney seem cocooned from the reality in Iraq.
A final note on which attacks work against which candidates. You'll notice that Edwards kept saying that Cheney was dishonest. This is an attack that would not have worked against Bush. People trust Bush, which is why Kerry generally says Bush is mistaken about Iraq, not dishonest. People are worried that Bush is distanced from reality, but they aren't worried about Bush's truthfullness. Similarly, Bush could have made the I've-Never-Met-You mistake that Cheney did, and no one would have cared. But people are already worried about Cheney's honesty, so he bleeds.