The infamous 'October Surprise'. Unlike Dan Rather's attempt, this one would stick.
As long as it wasn't recorded onto an 16GB SD memory card from a digital camera in 1973..:)
Either of those two, [plus many more Republicans] will resort to any measure to see that hillary secures the nomination...then the General. IMO.
Therefore, you can bet, hillary's camp would have already used it long ago if any such tape existed.