Donald Trump is right to extricate the US from Syria. American troops have no strategic reason to be in that country. If they stayed any longer they would only be sucked in deeper – if they tried to impose a sort of peace, they would be attacked by all sides. The outside world has no dog in the Turkish-Kurd fight.

The US should get out of Syria as it must leave Iraq, Afghanistan, Saudi Arabia and the Gulf.

Trump has been emphatic about withdrawal, but his unpredictability and aggressive rhetoric has muddied his intentions

While Trump’s motives or thought process for the latest move aren’t exactly clear – as ever – that he has enraged conservative and liberal interventionists alike is as reassuring as it is alarming. Belligerent meddling is now embedded in the west’s world view. But just as there is rarely a good time to intervene in other people’s troubles, so there is rarely a good time to stop. Were there a way in which a US army could swiftly bring peace and concord to northern Syria it might be different. There is none. Nothing in the modern history of the Middle East – not the Taliban or the Saddam or Assad regimes – has equalled the horror unleashed by the US’s “wars of 9/11”. They have come to seem as interminable as they are unspeakable.

As in any intervention, narratives evolve and alliances are formed. Most foolish was the encouragement and aid offered since 2015 to rebels in the Syrian civil war fighting against Bashar al-Assad – a war which David Cameron was inexplicably eager to have the UK join. As northern Iraq descended into chaos and the Kurds were emboldened to increase their pressure on Turkey, Syria became the venue for a nightmare three-way conflict. Throughout it, the US backed the Kurds.

The two most recent presidents, Barack Obama and Trump, came to office firmly in favour of withdrawing from the region. But the US’s military-industrial complex proved too powerful for them. Trump has been particularly emphatic about this, but his unpredictability and aggressive rhetoric has muddied his intentions. He has played hard and soft with Iran, tried to leave Afghanistan but not dared to do so, and now leaves the Kurds in the lurch.

When the outside world was united against Islamic State, a degree of strategic clarity was possible. Now Isis has, more or less, been bombed to pieces and older feuds have resurfaced. Trump has had enough. His desertion of the Kurds and his licence to Turkey to invade Syria must rank high in the annals of diplomatic treachery – but for realpolitik they are hard to fault.

Thus go all interventions. In seeking to mimic the global policing role of Europe’s 19th-century empires, American foreign policy has become an angel of disaster. Cities ancient and modern have been destroyed and religious faiths have been polarised and weaponised. Many people have died – possibly hundreds of thousands – and trillions of dollars have been wasted. It is as if the defeat of the Soviets in 1989 had cheated western armies of a third world war, leaving them determined to visit one on someone else – if not communism, then Islam. If Trump manages to end this self-defeating cycle, he deserves credit.

• Simon Jenkins is a Guardian columnist