When someone does a smear campaign, I just figure they're shit out of good things that they can do... so they try to bring the opponent down... I just try to think that the smear-er isn't able to do good, so they make the other look bad.
I think they're effective... HOWEVER... are they good? Absolutely not. What happened to the day where people like FDR were never photographed being lifted in a stretcher to get up to his speeches? Nowdays if say... Bush or Tony Blair or any of the world leaders were in that condition it would be blasted all over the news. Also people who have had divorce issues their papers will be used illegally to use against them. They're effective but immoral and I wish it didn't have to be that way, they shouldn't feel so insecure that they must use something negative on the enemy. People play dirty.