Educated voters see through this and vote the best they know how by being informed. Well, Martha, according to the political statistics, that barrage of last-minute exposure to your candidate's name is supposed to carry a lot of weight once a voter's in the booth. Campaign ads do influence voters. If sometimes only in a negative way. As Carrie mentioned, particularly tiresome mudslinging type ads can have an effect opposite of what was intended.
Voters are tired of negative campaigning.
However, there are still some positive campaign ads, mostly on the local level. And fewer all the time even there. So while I make it a point never to believe anything I hear in a negative campaign ad. I can't say I'm not influenced by them. But relax, folks.