The Swift Boat Veterans for Truth is a gang of liars who ran a thoroughly debunked TV ad in which they lied about serving with John Kerry in Vietnam and lied about his service record. Then the Bush campaign disavowed any connection to the Lying Swift Boat Veterans for Truth.
It was lying.
This New York Times infografic traces the financial connections between the organization and the Bush administration's staff, financiers, and cronies.
It also delves into the Lying Veterans' own on-the-record statements, like George "John Kerry has not been honest about what happened in Vietnam" Elliot's 1996 statement that "The fact that he chased an armed enemy down is not something to be looked down upon, it was an act of courage. And the whole outfit served with honor." Link (Thanks, bomark!)