Was Ronald Reagan’s dementia due to a true illness, or was it done through an external energy manipulation by the interlopers, as happened to President Joe Biden?

You have hit on the jackpot here with your beautiful creativity in seeing the parallels of presidents developing dementia while in office. As with Joe Biden, Pres. Ronald Reagan was attacked by the interlopers using the same kind of external energetic manipulation to disrupt his cognitive performance increasingly over time by fogging the mind. This became an increasing hindrance through inability to connect with memories important for him to function, as is true of all people. This was done as a punishment as well as an ongoing campaign to decrease his influence on things while still in office. Because he was a person of faith and under divine watch through the prayers of so many wanting his health and safety, we were able to delay the effects to some degree. But ultimately, we could not stem the tide as that would set a precedent and start a witch hunt by the Extraterrestrial Alliance and most certainly trigger a backlash to send ever more powerful energies of destruction into Reagan's brain as well as a risk of him being killed outright to win the contest.