The Middle East has a century old tradition of being the political graveyard of American and British political leaders. The list of casualties is long: Lloyd George, Anthony Eden, Jimmy Carter, Ronald Reagan, Tony Blair and George W Bush. All saw their careers ended or their authority crippled by failure in the region.

Will the same thing happen to Donald Trump as he struggles with the consequences of the alleged murder of Jamal Khashoggi? I always suspected that Trump might come unstuck because of his exaggerated reliance on a weak state like Saudi Arabia rather than because of his supposed links to Russia and Vladimir Putin. Contrary to the PR company boosterism of Crown Prince Mohammed bin Salman (MBS) and his ambitious projects, Saudi Arabia has oil and money, but is demonstrably ineffective as an independent operator.

The Middle East disasters that toppled so many Western leaders have a certain amount in common. In all cases, the strength of enemies and the feebleness of friends was miscalculated. Lloyd George was forced to resign as prime minister in 1922 because he encouraged the doomed Greek invasion of Anatolia which almost led to a renewed Turkish-British war.

George W Bush and Tony Blair never understood that the occupation of Iraq by American and British ground forces had no support inside Iraq or among its neighbours and was therefore bound to fail. A British military intelligence officer stationed in Basra told me that he could not persuade his superiors of the potentially disastrous fact that “we have no real allies anywhere in Iraq”.

The political debacle most similar to Trump’s ill-judged reliance on the Crown Prince and Saudi Arabia over the last three years was American policy towards the Shah and Iran in the years leading up to his overthrow in 1979. US humiliation was rubbed in when its diplomats were taken hostages in Tehran which torpedoed Carter’s hope of a second term in the White House.

Khashoggi disappearance: Forensic police investigate Saudi consul Show all 12 1 /12 Khashoggi disappearance: Forensic police investigate Saudi consul Khashoggi disappearance: Forensic police investigate Saudi consul According to local media reports, Saudi consul Mohammad al-Otaibi left Turkey on 16 October. A Turkish prosecutor on 15 October has entered the Saudi consulate in Istanbul to investigate the disappearance of dissident Saudi journalist Jamal Khashoggi, an inspection that was being carried out jointly with a Saudi team AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police officers work on the roof of the residence of the Saudi consul in Istanbul EPA Khashoggi disappearance: Forensic police investigate Saudi consul Khashoggi went missing on 2 October when he entered the Saudi consulate to pick up paperwork AP Khashoggi disappearance: Forensic police investigate Saudi consul ISTANBUL, TURKEY - OCTOBER 17: Turkish police arrive to investigate the Saudi Arabian consulate general residence as investigations continue into the disappearance of journalist Jamal Khashoggi on October 17, 2018 in Istanbul, Turkey. Turkish police first entered and searched the Saudi Arabian consulate on October 15 amid a growing international backlash about the disappearance. Khashoggi, a U.S. resident and critic of the Saudi regime, has been missing since visiting the Saudi Arabian consulate on October 2. Turkish officials have said they believe he was killed inside. (Photo by Chris McGrath/Getty Images) ***BESTPIX*** Chris McGrath Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic and investigation officers arrive at Saudi Consul's residence on October 17, 2018 in Istanbul. - Saudi Arabia's consul to Istanbul Mohammed al-Otaibion on October 16, 2018 left the Turkish city bound for Riyadh on a scheduled flight, reports said, as Turkey prepared to search his residence in the probe into the disappearance of journalist Jamal Khashoggi. (Photo by OZAN KOSE / AFP)OZAN KOSE/AFP/Getty Images OZAN KOSE AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police arrive to investigate the Saudi Arabian consulate general residence Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police search for evidence at the garden of the Saudi Arabia's Consul General Mohammad al-Otaibi AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police search the rooftop of the Saudi Arabian consulate general residence Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police arrive at the residence of the Saudi consul General Mohammed al-Otaibi to conduct a search AP Khashoggi disappearance: Forensic police investigate Saudi consul Turkish police officers gather as they prepare to enter Saudi Arabia consul's residence, in Istanbul, Wednesday, Oct. 17, 2018. America's top diplomat is in Turkey, where a strongly pro-government newspaper has published a gruesome recounting of the alleged slaying of Saudi writer Jamal Khashoggi at the Saudi Consulate in Istanbul. (AP Photo/Petros Giannakouris) Petros Giannakouris AP Khashoggi disappearance: Forensic police investigate Saudi consul Turkish forensic police search for evidence at the garden of the Saudi Arabia's Consul General Mohammad al-Otaibi AFP/Getty Images Khashoggi disappearance: Forensic police investigate Saudi consul ISTANBUL, TURKEY - OCTOBER 17: Turkish police search the rooftop of the Saudi Arabian consulate general residence as investigations continue into the disappearance of journalist Jamal Khashoggi on October 17, 2018 in Istanbul, Turkey. Turkish police first entered and searched the Saudi Arabian consulate on October 15 amid a growing international backlash about the disappearance. Khashoggi, a U.S. resident and critic of the Saudi regime, has been missing since visiting the Saudi Arabian consulate on October 2. Turkish officials have said they believe he was killed inside. (Photo by Chris McGrath/Getty Images) Chris McGrath Getty Images

There are striking and instructive parallels between US and British policy towards Iran in the lead up to the revolution and towards Saudi Arabia in 2015-18. In both periods, there was a self-destructive belief that an increasingly unstable hereditary monarchy was a safe bet as a regional ally as well as being a vastly profitable market for arms.

The Shah and MBS both promoted themselves as reformers, justifying their authoritarianism as necessary to drag their countries into the modern era. Foreign elites fawned on them, ignored their weaknesses, and were fixated by the mirage of fabulous profits. A British ambassador to Iran in the 1970s was said – I quote from memory – to have rebuked his embassy staff with the words: “I don’t want any more elegantly written reports about social conditions in Iranian villages. What I want is exports, exports, exports!”

Brexit has taken Britain off the world stage and it must be happy in future with whatever crumbs it can scrounge in Saudi Arabia or anywhere else. But Trump sounds very much like this long-forgotten ambassador when he justifies the US strategic alliance with Saudi Arabia by referring repeatedly to a $110bn in arms contract.

In practice, hereditary monarchies are at their most unstable during a leadership transition, attempts to reform, efforts to expand as regional powers or as initiators of war. In England, the pacific and cautious King James I was succeeded by his arrogant, arbitrary and incautious son, King Charles I, with unfortunate consequences for the monarchy.

Vulgar display was a feature of the Shah’s Iran 40 years ago as it is of Saudi Arabia today. In his case, there was the celebration of 2,500 years of the Persian Empire at Persepolis in 1971, which fed the ruling elites of the world with exotic delicacies such as 50 roast peacocks with tail feathers restored and stuffed with foie gras along quail eggs filled with caviar, which the Shah could not eat because he was allergic to caviar.

The Saudi equivalent to Persepolis is the much-publicised “Davos in the Desert” or, more prosaically, the “Future Investment Initiative” being held this week in Riyadh and from which politicians and businessmen have been very publicly dropping out as mystery over the disappearance of Khashoggi has deepened. Much of the media is treating their decision to stay at home as some sort of moral choice and never asks why these luminaries were happy to act as cheerleaders for Saudi Arabia in the same time the UN was warning that 13 million Yemenis are on the verge of starvation because of the Saudi-led military intervention.

It is no excuse for the Trump administration or the defecting guests in Riyadh to claim that they did not know about Saudi Arabia’s potential for random violence. As long ago as 2 December 2015, the German federal intelligence agency, the BND, published a memo predicting that “the current cautious diplomatic stance of senior members of the Saudi royal family will be replaced by an impulsive intervention policy.” It went on to say that the concentration of so much power in the hands of Prince Mohammed bin Salman “harbours a latent risk that …he may overreach.”

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The memo was hurriedly withdrawn at the insistence of the German foreign ministry, but today it sounds prophetic about the direction in which Saudi Arabia was travelling and the dangers likely to ensue.

Trump has put a little more distance between himself and the Crown Prince in the past few days, but he makes no secret of his hope that the crisis in relations with Saudi Arabia will go away. “This one has caught the imagination of the world, unfortunately,” he says though he may believe he can shrug off this affair as he has done with so many other scandals.

Just for once, Trump’s highly developed survival instincts may be at fault. His close alliance with Saudi Arabia and escalating confrontation with Iran is the most radical new departure in Trump’s foreign policy. He withdrew from the Iran nuclear deal in defiance of the rest of the world earlier this year on the grounds that he can extract more concessions from Iran by using American power alone than Barack Obama ever did by working in concert with other states. This struggle is so important because it is not just between the US and Iran but is the crucial test case of Trump’s version of American nationalism in action.

The White House evidently calculates that if it draws out the crisis by systematic delaying tactics, it will eventually disappear from the top of the news agenda. This is not a stupid strategy, but it may not work in present circumstances because the Saudi authorities are too inept – some would say too guilty – to produce a plausible cover story. The mystery of Khashoggi’s disappearance is too compelling for the media to abandon and give up the the chase for the culprits.