It is justifiable to bar someone from office because of what might happen to them? Someone can be fit for office and could remain so until the day they die, but they shouldn't be allowed to hold that position because something might happen to them at some undetermined point in the future?
Adults aren't children. Below a certain age no one should be able to drive a car. Above a certain age only some individuals shouldn't be able to drive a car.
Is age the only risk factor you're concerned about? Should we ban people who smoke? Drink too much alcohol? Are above a certain height? Have HIV? Are disabled?
If your answer is no I ask once again. Why is it okay to discriminate against one adult for the qualities of another? Since risk of them becoming unable to execute the duties of the office isn't the main factor.
Risk of them becoming unable to execute the duties of the office is a main factor. It's ok to discriminate against adults for the qualities of a high risk of developing age-related degenerative disorders over the course of their tenure.
This isn't that hard to understand. Your line of reasoning is pointless.
A bunch of people are living in the delusional reality of an old person and it's pushing us close to civil war for no good reason beyond boomer mass dementia. You have failed to understand the present crisis, so you fail to comprehend the necessity for this simple preventative measure.
I'm just trying to convey how a purely age based limit is prejudiced and inconsistent with what you have said. It seems an awful lot like you are basing someone's worth on their age rather than their expressed values, or their actual observed health and state of mind.
If what you care about are in fact their values, and health then their age should be irrelevant. You can be young and sick, or old and healthy. Age is a correlation. Not a cause.
If the limit was 60 that means half of all US presidents would have been ineligible to hold office.