Humiliation can be very painful, and Americans who are aware of foreign events will be feeling very hurt at the moment. It is rarely fatal even for individuals, however, and almost never for countries. They should take solace from Adam Smith’s remark on the occasion of another military debacle.

The great Scottish economist and philosopher was replying to a letter from a distraught friend who feared that the British defeat in the Battle of Saratoga in 1777, which was the decisive turning point in the American Revolutionary War, meant that Britain was ruined. Smith told him not to worry: “There is a great deal of ruin in a nation.”

He was right, of course. What really lay ahead for Britain was a century and a half as the world’s greatest empire and its dominant economic power. There is certainly no guarantee that a similar future awaits the United States, but history is capricious and almost all outcomes are imaginable – so panic and despair are inappropriate responses.

The Afghanistan war was a huge and long-lasting US mistake, but America’s humiliation there does not significantly diminish the country’s economic, military and strategic advantages (which are very great indeed). Its cultural prestige is a bit dented, but memories are short and it will soon recover.

President Joe Biden’s posture, realistic but not defensive, will help the recovery. Afganistan was a preposterous 20-year waste of money and lives, but presidents Bush and Obama both shirked the necessary decision to cut American losses and end it.

President Trump finally bit the bullet and set the deadline for withdrawal, which Biden enforced with only a slight extension. And while the humiliation of yet another American defeat is intense in the short term, it is (if you will excuse the expression) a ‘learning opportunity’ for the United States in the longer term.

The problem that has led to repeated US military fiascos like Vietnam, Iraq and Afghanistan, in the view of Dr George Friedman, founder of Stratfor and later of ‘Geopolitical Futures’, is that the United States has become addicted to what he calls ‘non-strategic wars’. Or ‘wars of choice’, in the common usage.

The first use of that phrase was by Israel’s then prime minister, Menachem Begin, about the invasion of Lebanon in 1982. I was in Israel for that war, and Begin sounded proud, almost arrogant, as he contrasted it with the wars of ‘no alternative’(1948, 1973) when Israel fought to defend its vital interests or its very existence.

His arrogance came from the fact that by the 1980s Israel was the Middle East’s dwarf superpower, no longer seriously vulnerable to attack and free to make punitive attacks on its neighbours whenever it felt like it. There were dead Syrian tanks all over the Beka’a valley but hardly any Israeli ones, and the kill ratio in the air was 86-0 for the Israelis.

The United States is still cautious when there is a risk of war with another great power. However, it has been so dominant militarily for so long that wars with lesser powers are seen as an option to be exercised or not according to the political fashion or even the moral mood of the moment.

Hence Vietnam (anti-Communist paranoia and the ‘domino theory’); Grenada and Panama (old-fashioned imperialism); Serbia and Kosovo (moral mood); Afghanistan (panic about terrorism plus moral mood); and Iraq (broad-spectrum ignorance). Plus a dozen lesser military interventions from the Bay of Pigs to Libya.

I have omitted the Korean War and Gulf War of 1991 because both were fought to defend a world order beneficial to the United States. All the rest, however, were wars of choice: winning or losing them meant nothing in terms of the vital strategic interests of the United States. The US won some of the little ones, but lost all the bigger ones.

The United States has fallen into the habit of frittering its strength away in non-strategic wars against countries that do not really threaten it. This ultimately undermines American power, and in the country’s own interest (as well as the world’s) it should change its ways.

The humiliation in Afghanistan is a chance for Americans to reconsider their country’s behaviour. As Rudyard King wrote at the end of the second Boer War in 1901, “We have had no end of a lesson: it will do us no end of good.”

Of course, the British didn’t really change their ways. Old habits die hard.