I am old enough to remember in 1984 there were already stories about Reagan's very real cognitive decline.
"I do not recall" became a meme before people knew what Memes were
Did his party abandon him? No. Reagan won in a landslide in 1984 and governed well enough that voters rewarded his party by electing His VP Bush
I am Riding with Biden
All his key people essentially reported to NANCY and she ran the country for Ronnie.
@Kinnison
One of my ex's was fairly high ranking and it was unbelievable what went on then. Remember, this was also the time when Nancy consulted her Astrologist regularly... so she wasn't running the country alone.