Will the zero curse stop Biden?

A related positive factor is the improved overall level of health of Americans. They work in healthier conditions, with a reduced risk of being caught in fire traps, reduced smoking, and the limitations on the consumption of drugs and alcohol in the workplace. Americans are therefore living longer than ever before.

American presidents – even elderly ones like Biden – are entering office with a healthier lifestyle. They are also subject to more sophisticated daily health monitoring that were most of their predecessors.

On the other hand, the job is even more demanding. An Australian prime minister is simply the "first among equals" and while tempted to have a unilateral "captain's pick" occasionally, they must keep their colleagues on their side, or else risk being removed from office by their colleagues, as Hawke, Rudd, Gilliard and Abbott all found.

A US president by contrast is more like a king, and the cabinet is simply composed of advisers. A president cannot suffer from a backbench revolt and so be removed by his own colleagues (unless Congress finds he has committed high crimes and misdemeanours).

On the other hand, the president makes all the key decisions – if necessary, without consulting anyone. It is interesting to see how a term in office "ages" a president. They look much greyer and wearier when they leave office.

Additionally, the communications revolution has accelerated the need for speedy decisions and less time for reflection. There is the constant stress and wear and tear of office, with strict limitations on how a president can delegate his authority. He is at work for four years straight, whether in the US or overseas, at say a conference. There is no let up.

Finally, there is the US's notorious gun culture. Of the seven dead 'zero year' presidents, four were shot.

American political culture is ambivalent on how much a president should be shielded from the general public. On the one hand most citizens do not want their president shot, and he has continual, somewhat intrusive, secret service protection.

On the other hand, there is a requirement for openness and accessibility. He has to 'press the flesh' in campaigning and mix with crowd. The White House itself is not protected by a high wall but gives the impression of an ordinary fence through which people can see and even climb over (although the secret service is alert to such risks).

Modern weapons are a lot more dangerous than the pistols of the old days. There is also the new factor of a drone attack.

The zero year curse hangs over Biden for as long as he remains in office, whether that is until January 2025 or (if re-elected) January 2029.

Keith Suter