It can’t be proved. That is the problem with all of the vaccines including the Covid shot. (I personally experienced vocal cord damage following my 3rd Hepatitis shot in 1994. I was just recovering from my 3rd cold in 1 month when I was given the booster. I was young, naive and believed when I was told it was okay to take while recovering from another cold. I believe my immune system was low and the damage happened as a result. I, to this day, suffer vocal cord damage. As a registered nurse I had to force myself to go into patient rooms and do discharge teaching. Nurses talk a lot and I had severe throat tightening and diaphragm fatigue. I was resistant to the botulism toxin injections given to paralyze the one vocal cord from spasms. The treatment was supposed to last 10-12 months. The first one only helped 3 months and the 5th and last, 12 hours. What helped me the most was acupuncture in the neck with electrical stimuli. My voice was 95% normal immediately after. However, that treatment was in Canada, and I live in the U.S. so I could not commute twice a week as suggested and none of the acupuncturists I have gone to in the U.S. would do the same mode. It did improve my speech and stopped the diaphragm fatigue, so I count myself lucky.) Robert Kennedy Jr. has a very bad case of spasmodic dysphonia and I do not think he will be able to get voters to overlook this obstacle. But I think he would make a great VP running mate and together the two could unite the country. He would then prove himself and go on to run as President. I think voters will view his spasmodic dysphonia as a handicap. But he could be used as a melding of the two parties together: Democrat and Republican. Maybe it is wishful thinking on my part! Lol.