Seth Godin on political ads:
Political TV advertising is designed to do only one thing: suppress the turnout of the opponent’s supporters. If the TV ads can turn you off enough not to vote (“they’re all bums”) then their strategy has succeeded.
There are positive ads as well that are intended to encourage turnout from supporters, but there’s no doubt that he’s right about negative ads.
Here’s my strategy for choosing who to vote for: I never vote for crooks. If a politician seems to be a crook, I won’t vote for them regardless of party. Then I vote for the party whose goals align most closely with my own, regardless of the individual candidate (as long as they’re not a crook).