The Age-Old Question: Is Biden Fit to Lead?

As President Joe Biden faces mounting scrutiny over his cognitive abilities, the nation grapples with a fundamental question: How do we measure a leader's mental fitness? In the wake of Biden's widely criticized debate performance and subsequent ABC interview, medical experts are weighing in on the complex science of aging and cognition.

The President, now 81, insists he's up to the task. "I don't think anybody's more qualified to be president or win this race than me," Biden told ABC's George Stephanopoulos. Yet his assertion that he receives "a full neurological test every day" has raised eyebrows among medical professionals.

Dr. Charan Ranganath, a neuroscience professor at UC Davis, explains that cognitive decline is a nuanced process. "Not everything declines as you get older, and not everything declines at an equal rate," he says. While fact recall may slow with age, other crucial presidential qualities—like moral reasoning and empathy—can actually improve.

The debate over Biden's fitness taps into broader concerns about aging leadership. By age 80, more than 25% of people may experience some form of mild cognitive impairment. But as Dr. John Rowe of Columbia University points out, "Some get impaired with age, and some actually get better with age, such as vocabulary."

Experts like Dr. Emily Rogalski of the University of Chicago advocate for comprehensive evaluations that go beyond simple screening tools. These assessments can include neurological exams, blood tests, brain imaging, and interviews with family members—painting a fuller picture of an individual's cognitive health.

As the 2024 election looms, the question of presidential fitness transcends partisan lines. Dr. Rowe suggests that cognitive testing should be standard for all presidential candidates, regardless of age. "If somebody fails a test," he argues, "I think that's something that people should know."

Yet even as medical science advances, the art of leadership remains difficult to quantify. As the nation watches Biden navigate this unprecedented scrutiny, Americans are left to ponder: What exactly do we expect from our leaders in their golden years, and how do we measure the intangible qualities that make a great president?

* CNN contributed to this article.