Volokh linked to this site that contains old tv political ads. It is quite interesting to see how nasty the ads have always been all the way back to the 1950s. The one exception that stands out even when the ad was an attack ad - Ronadl Reagan! Thos are the only truly optimistic and happy ads (even the one attcking Carter is filled with hope for lower inflation). The ads are almost non-political. A combination of Michael Deaver and the Gipper's personality get the credit.