Negative political ads turn off prospective politicians from engaging in politics. When young people see people that they look up to and some day want to become attacking other people that they look up to, they no longer want to be those people any more. Negative ads take away children's dreams.
Negative ads are so common during elections, and have turned into direct personal attacks on a candidates rather than informative conversations. Although I think the public has a right to get a correct perspective on any candidate, I would rather learn how they will vote from their history of service, their beliefs, and morals on pertinent subjects. This should come directly from the politician, rather than from negative ads that cloud the already murky waters beyond seeing how that potential politician would behave as politician.