The near-unanimous consensus of gerontologists in the past several decades has been that elderly people are more cognitively capable and adaptable than our prejudices indicate. The vast majority of people in their 70s do not show signs of dementia. While it is true that subtle cognitive decline is nearly inevitable for all of us, different sorts of intelligence are affected at different rates. Indeed, the effects of aging are far from homogenous or predictable, which is why we reject Robert Kaiser’s recent suggestion that the risk of mental decline is grounds for disqualifying older candidates.

History shows that it is a dangerous game to politicize clinical data about a certain group’s “intelligence” or capacity. Even if one did want to play that game, it remains to be argued whether the specific sorts of reasonably expected decline would lead to incompetence in the specific tasks of the modern American presidency — which are, to state the obvious, not the tasks replicated in the lab.

The question of whether elderly people are suited for executive office can be better answered with the tools of history. And history suggests that they are: South African leader Nelson Mandela, Britain’s Winston Churchill and Konrad Adenauer, chancellor of West Germany for 14 years after the end of World War II, were all highly effective political leaders well into their 70s.