To selectively edit video or audio for the sheer denigration of your political opponents. Must be used under the guise of humor.
Much like how its synonym Breitbarted is named for Andrew Breitbart, 'leibowitzed' is named after Jon Stewart and the Daily Show.
Did you see Palin getting leibowitzed on the Daily Show last night?
It might not have been fair, but it sure was funny!