If politicians on the left of the US political spectrum believe they are being unfairly attacked or smeared, they will often refer to the attacks as "swift-boating", in reference to the series of anti-John Kerry adverts aired in the run-up to the 2004 presidential election by a 527 group called the Swift Boat Veterans for Truth.

The adverts featured veterans who - like Mr Kerry - served on naval craft known as "Swift Boats" in Vietnam and who were critical of Mr Kerry's record in the war.