the Daily show played some footage of the not so swift & not so truthful veterans from a previous campaign standing next to Kerry and praising his actions under fire. same guy who said Kerry Lied.

the whole point is that the Republicans know that smear campaigns work. According to studies of previous elections, a large number of people - those that are undecided dont think about issues, they think about how a candidate looks, or soundbytes or the 'gotcha' factor.

in the 92 election, 80% of people polled knew that GHW Bush's dogs name was Millie, but only 15% knew where Clinton and Bush stood on capital punishment (they were both for).

or minor points or incidents are blown into big issues, like GHW Bush didnt like Broccoli, or Gerald Ford in the 76 election trying to eat a tamale without removing the corn husk. (people of mexican background would have deduced that since Ford was unaware of how to eat a tamale, issues involving them would be a low priorities.)
when asked about the election afterwards Ford said 'always peal your tamales'

equally GHWBush's surprise on learning that all supermarket checkouts had laser scanners in a supermarket tour - something that had been around for a decade.

the list goes on, in Canada in the 72 election the image of R. Stanfield fumbling a football (even though hed caught a bunch of them without a problem but thats the one that the press used) was the image that helped him lose that election to Trudeau.

the fact is a lot of people dont really think much about the real issues, and the Republican campaign managers know it, and use it to great effect.

the did it to Mcain, accusing him of being unpatriotic -
and to Max Clelland who lost 3 limbs in Vietnam (Ran a picture of him next to Saddam Hussein) ironic that no one in the Whitehouse now
(excepting Powell) actually served in Combat. (Bush was awol, and Cheney had other priorities) and theres a great clip of Rumsfeld running up to Saddam in the 80s and pumping his hand.