Clinton's 100 Percent Negative In PA?

PHILADELPHIA -- That's the claim of the Obama campaign, one repeated in a fundraising solicitiation sent by Obama camapign manager David Plouffe. Phil Singer, a Clinton campaign spokesman, says that his campaign is airing both positive and contrast (negative) ads in every PA market. Both campaigns track each other's ad purchases, so one would assume that both campaigns would have evidence to support their positions here, but neither campaign has been forthcoming. If any reader has seen a positive Clinton commercial on television, e-mail me so we can put this question to rest.