There was a campaign in my area during the 2002 congressional race that involved a fellow named Jack Machek (D) and his opponent Tim Murphy (R).
Jack Machek had a campaign flier that stated that he had attended West Point but that he had graduated from the University of Pittsburgh. Jack was very proud of his West Point acceptance but he had been honorably discharged after he had suffered a hearing loss due to an extended illness.
This was an open congressional seat...and Tim Murphy wanted to win so he wanted to demonize Jack so his campaign staff went about saying that Jack had LIED on his campaign flier because he hadn't graduated from West Point and he had no right to put it on his flier...
In fact they got this veteran (whose son graduated from West Point but was paralyzed in an auto accident) to follow Jack around to public events to bring up this topic over and over and over again.....so that no one paid attention to the issues.
Now I don't know how much influence this had on the campaign but Jack lost and I know that a number of Democrats brought up this issue.
edit: Here is a link which mentions some of the hoopla over this...
http://www.post-gazette.com/election/20021106congress1106p4.aspIn retrospect I have to say that Jack's campaign advisors should have not mentioned anything about the military but then again Tim Murphy got out of Vietnam by attending college....so really I think it was just plain old vanilla nasty politics...