The term swiftboating (also spelled swift-boating or swift boating) is an American neologism used pejoratively to describe an unfair or untrue political attack. The term is derived from the name of the organization "Swift Boat Veterans for Truth" (SBVT, later the Swift Vets and POWs for Truth) because of their widely publicized[1] then discredited campaign against 2004 US Presidential candidate John Kerry.[2][3][4]
I understand that some people don't like Kerry because he had the moral courage to speak out against the war, but to try to discredit him means that a number of other people, by association, were also discredited. A shameful act against patriots just for political gain.