A competent defense attorney would have attempted to discredit all the eyewitness testimony against Saint Patsy and might have even had some success with that, but he wouldn't have discredited it all or gotten it thrown out.
And after reviewing the accumulated eyewitness testimony, physical and circumstantial evidence -- the jury would swiftly find Saint Patsy guilty of assassinating JFK (and murdering JDT).
Ask Gerry Spence.