“We’re offering a very fair and reasonable DEAL, and I hope they take it because, if they don’t, the United States is going to knock out every single Power Plant, and every single Bridge, in Iran.” Familiarly genocidal threats from Donald Trump, with the trademark mobster-style “NO MORE MR NICE GUY” at the end. Amazing how fast you get used to it.

There may be another ceasefire by the time you read this, or 92 million Iranians may be learning to live with no electricity, little food and no water. (In other rants he threatens Iran’s desalination plants and its bridges, crucial for getting food to the cities.) In either case, the regime’s leaders, all survivors of his assassination attempts, remain unyielding.

Trump regularly has “good conversations” with the civilian and Islamic Revolutionary Guard leaders, many of them entirely imaginary. But just beneath the surface he’s as frantic as a trapped rat, unable to understand why the Iranians won’t give in although “they have no cards”. (Wrong: they have weapons, patience, faith and, above all, favourable geography.)

He can’t admit even to himself that Israel’s Prime Minister Binyamin Netanyahu tricked him into this doomed enterprise, because that would be to admit he has been fooled. John Kennedy took the blame for the Bay of Pigs disaster and walked away. Trump cannot do either of those things, so he keeps reinforcing failure.

If this were just a personal and political disaster for Donald Trump and his associates, few people outside the United States would see it as a tragedy, and neither would about half of the American population. However, if it also involves a permanent decline in US power in the world, most Americans and many people elsewhere would see it as an unwelcome change.

The key word here is ‘permanent’. In fact that collapse has already occurred, as witness the almost unanimous refusal of America’s erstwhile allies to get involved in Trump and Netanyahu’s ‘war of choice’ against Iran, but it is so recent that a recovery still seems possible. Maybe it is, and maybe not.

Economic strength was always the key factor in any system of states, with military power mainly determined by a country’s industrial production. By that traditional measure the United States has long been in relative decline (it produced more than half the manufactured goods in the world in 1945, but only 16% now.)

However, the United States has remained the foremost power because it spends a lot on a very high-tech military (eight times China’s spending) and it continues to lead in science, in finance and in intellectual property. Those more or less intangible assets are more easily lost, however, and they are what is currently at risk because of Trump’s presidency.

In the past five centuries there have been three transfers of dominance in the European state system, which expanded over that period to include the whole world: from Spain to France in about 1620 (the Thirty Years’ War); from France to Britain in about 1800 (the Napoleonic Wars), and from Britain to the United States around 1940 (peacefully).

On the current assumption that China is the next obvious candidate, a hopefully gradual and non-violent transfer should occur in the next half-century, which would give both China and the rest of the world time to get used to the idea. But what if the United States falls out early?

Trump has already seriously damaged America’s reputation as a potential ally or partner, and he’s not finished yet. Several American experts are already talking about the possibility of a civil war, and Trump himself came close to endorsing a coup attempt in January 2021. Countries that are fighting civil wars automatically lose the crown.

At the same time, China’s claim to be the inevitable successor to the role of First Among Equals is rapidly being undermined by the demographic collapse that is already getting under way in the country. It will halve the population by the end of the century, and the economic damage will probably be as grave as the demographic effects.

The dark horse in the race is India, whose population will still be around 1.5 billion in 2070 when China’s has already fallen below one billion, heading down towards 730 million by 2100. But that would only give India the prize if it manages to duplicate China’s feat of thirty years of high-speed economic growth (10%-plus annually), which is far from assured.

Let’s face it. We cannot see even dimly that far into the future, and besides we should hope and work for a time when that kind of pecking order among the great powers is no longer major consideration in international affairs.

Gwynne Dyer’s new book is ‘Intervention Earth: Life-Saving Ideas from the World’s Climate Engineers’. The previous book, ‘The Shortest History of War’, is also still available.