Separated by 16 years, two of the most famous and controversial TV ads in presidential campaign history share a remarkable set of traits. Both were launched by nominally independent groups, not by the candidates themselves. Both aired in just a few small markets, gaining widespread exposure only through news media coverage. Both were denounced as inaccurate and unfair.

And both the "Willie Horton" spot of 1988 and the 2004 campaign's initial commercial by Swift Boat Veterans for Truth slammed a Democrat from Massachusetts and helped a Republican candidate named George Bush.

In both the Horton and Swift boat cases, the respective Bush campaigns disclaimed responsibility, saying the ads were the work of unaffiliated groups. But in both instances, news media reports subsequently exposed ties between the official campaigns and the independent groups.