Call them phantom footnotes.
It's the practice of making a controversial charge against your opponent - and then citing a reputable source to back up your claim.
These footnotes appear on brochures, fliers, and in television commercials in Congressional and statewide races.
But sometimes when the source is checked, it doesn't back up the original accusation.
http://www.courant.com/news/politics/hc-phantom-footnotes-1026-20101025,0,4879527.story