The Badger, here's an answer to your question from

Swiftboating is American political jargon that is used (primarily) as a strong pejorative description of some kind of attack that the speaker considers unfair—for example, an ad hominem attack or a smear campaign.

The term comes from the Swift Vets and POWs for Truth (formerly "Swift Boat Veterans for Truth") and their widely-publicized [1] attacks on 2004 Presidential candidate John Kerry...

Originally, terms like "swiftboating", "Swift Boating", "Swift Boat tactics", etc. were mostly used by people who disapproved of the Swift Vets and POWs for Truth. Others have strongly objected (see below) to the criticism of SBVT implied by such negative usage.

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The entire entry is at http://en.wikipedia.org/wiki/Swiftboating

mg, I hear your objection, and want you to know that I don't consider ALL those military personnel who served/serve as swiftboaters to be negative. Also, mg, I'm very sorry that this referent has taken on this negative connotation because of the group-the so-called "Swift Boat Veterans for Truth"- which I and quite a number of other folks consider to be extremely negative.