If I were to want to edit a piece of video that I had legally acquired, entirely within the scope of Fair Use and not for any purpose of copyright infringement...
...as a last resort, if all else failed, I'd open the segment in QTPro and export it as an image sequence, 29.97 frames per second. I'd then recombine that image sequence back into a movie using QTPro.
Sound would be lost during this process, but it would be a trivial matter to use FCP or something to extract a sound file from the original source material and recombine the extracted sound file with the newly created movie.