Hey, I hear you, but the age cutoff could also be on holding office.

As someone just hitting the 60 yr old mark, and looking at my parents who are still pretty sharp in their late 80s, -- so definitely talking about myself and my capacity here,

No-one over 70 has any business in a high ranking government office. The mental flexibility isn't there.

Which means no one over 66 should be allowed to run office (yes, I know this puts senators in office until 72, and kicks out representatives at 68, but it also gives a single number which is easier to understand).

It's also a question of accountability. A 40 year old politician will expect/have to live with their choices for another 40 years.