pseudo-country-bumpkin wisdom uttered in response to news item or rumor designed to scandalize a political opponent.
The idea is that the rumor is either very easily refuted or is unimportant to the public, and thus is as worthless as a dog who won't hunt.
Bush is trying to spread rumors about Kerry's Vietnam record but that dog won't hunt.
Free Daily Email
Emails are sent from firstname.lastname@example.org. We'll never spam you.