Republican presidential candidate Nikki Haley calls for "lucidity" tests for US politicians over 75 years to check they remain mentally competent.
It's natural to stumble sometimes when you're running the most powerful country in the world. But Joe Biden is about to turn 81, and age threatens to be one of the issues that will come up in the next US presidential elections.
Questions have multiplied whenever there are incidents that suggest mental confusion, whether it's the Republican leader in the Senate, Mitch McConnell, who is also 81, or the Democrat Nancy Pelosi, 83, who is seeking to return to the leadership of the House of Representatives.
Haley's suggestion of lucidity tests (a "basic mental test") is one response to the issue.
But doubts that are emerging are not just about lucidity, but about health in general and problems that could mean absences from work. The White House, for example, claims that Biden undergoes an annual battery of medical tests to confirm his fitness for the job, but no details are released about the nature of these tests.
Limiting the number of terms in office is a way of partly managing the issue, but it doesn't work for septuagenarian, or even octogenarian, incumbent, who is up for re-election.
And when the comparison is made with Europe, where the systems are mostly parliamentary, the differences are more than blatant: they're actually at the other end of the scale. Rishi Sunak, Emmanuel Macron and Giorgia Meloni are still in their 40s, for example (they're 43, 45 and 46 respectively).
- Average age - 53
- Oldest - Germany's Chancellor Olaf Scholz 65
- Youngest - Ireland's Prime Minister Leo Varadkar 44
- 6 people (20%) aged 60 or over
- 13 people (44%) aged 50 or under
- Average age - 62 (if we exclude European leaders, the average age rises to 65)
- Oldest - US President Joe Biden 80
- Youngest - Saudi Arabia's Crown Prince Mohammed bin Salman 38
- 6 people (26%) aged 70 or over
- 5 people (21%) under the age of 50
- Average age - 64.15
- Oldest - Republican Senator Chuck Grassley 90
- Youngest - Democrat Senator Jon Ossof 36
- 1 aged 90, 5 aged 80 or over
- 34 (34%) aged 70 or over
- 68 (68%) aged 60 or over
- 11 (11%) aged 50 or under
Average life expectancy has increased exponentially in many countries, although in the United States it has fallen from a high of 79 years in 2019 to 76 years in 2022.
And according to Michelangelo Vercesi, a researcher at the Portuguese Institute of International Relations at the New University of Lisbon, "normally, prime ministers used to take office after accumulating a lot of experience in parliament, in the party and in government."
"But now we have more and more outsiders with less political experience, more technical experience and who are young. In these cases, the question of age perhaps lies in what prime ministers do once they are in office."
There is already a minimum age for voting or running for certain public offices. Imposing an upper limit would be a form of discrimination that constitutions generally prohibit. And in any case, anyone who casts their vote in the ballot box knows who they are choosing.