A rather lengthy but revealing article from "Atlantic Monthly" about the history of Karl Rove's devious campaign history:
http://www.theatlantic.com/doc/200411/greenKarl Rove in a Corner
Karl Rove is at his most formidable when running close races, and his skills would be notable even if he used no extreme methods. But he does use them. His campaign history shows his willingness, when challenged, to employ savage tactics
by Joshua Green
<snip>
If this year stays true to past form, the campaign will get nastier in the closing weeks, and without anyone's quite registering it, Rove will be right back in his element. He seems to understand—indeed, to count on—the media's unwillingness or inability, whether from squeamishness, laziness, or professional caution, ever to give a full estimate of him or his work. It is ultimately not just Rove's skill but his character that allows him to perform on an entirely different plane. Along with remarkable strategic skills, he has both an understanding of the media's unstated self-limitations and a willingness to fight in territory where conscience forbids most others.
Rove isn't bracing for a close race. He's depending on it.