Trump says Isis has been defeated, but he is ignoring the bigger and much more worrying picture

President Trump says that in the coming week the US and its allies will announce that they have captured all of the land previously controlled by Isis. He claims that US-led forces “have liberated virtually all of the territory previously held by Isis in Syria and Iraq … we will have 100 per cent of the caliphate.“

The prediction has sparked a sterile and misleading debate about whether or not Isis is finally defeated, something which will remain unproven since the movement is unlikely to run up a white flag and sign terms of surrender. The discussion has – like all debates about foreign policy in the US – very little to do with the real situation on the ground in Syria and Iraq and everything to do with the forces at play in Washington politics.

In discussing the demise or survival of Isis, pundits make the same glaring omission. They ignore the fact that by far the largest stronghold in Syria held by an al-Qaeda type group is not the few shattered villages for which Isis has been battling in the east of the country. Much more important is the jihadi enclave in and around Idlib province in north-west Syria which is held by Hayat Tahrir al-Sham (Liberation of Levant Organisation), a powerful breakaway faction from Isis which founded the group under the name of Jabhat al-Nusra in 2011 and with whom it shares the same fanatical beliefs and military tactics. Its leaders wear suicide vests studded with metal balls just like their Isis equivalents.

It is not that the US has any doubts about what HTS is – since last year, a foreign terrorist organisation despite a name change. Nathan A Sales, the State Department’s coordinator of counterterrorism, noted that “today’s designation serves notice that the United States is not fooled by this al-Qaeda affiliate’s attempt to rebrand itself.”

Over the past year HTS has expanded its control to almost all of the Idlib enclave, which the UN estimates to have a population of three million, half of whom are refugees, and can put at least 50,000 fighters into the field. The zone is surrounded on three sides by the Syrian Army backed by the Russians and on the fourth side it shares a common border with Turkey whose local proxies it has crushed. Fighting between Assad government forces and the armed opposition in Idlib has largely died away under the terms of a shaky ceasefire agreed and enforced by Moscow and Ankara.

Blindness in the west to this embattled al-Qaeda-run mini-state, which has a population the same size as Wales and a fighting force not much smaller than the British army, is explained by the fact that such an admission would reveal that the US and its allies are weak players in Syria and there is more than one jihadi group in the country. A recurrent and disastrous theme of western involvement in the war in Syria is for governments and media to focus only on part of the multilayered crisis in which they are engaged.

Pretending that Isis is anything close to the potent threat it used to be is part of the struggle between Trump and the foreign policy and security establishment in Washington. They represent what President Obama derided as “the Washington playbook” which he denounced as always looking to military solutions and always overplaying its hand in fighting wars that never end.

This skewed vision of the Syrian conflict – with its over-emphasis on whether or not the death certificate of the caliphate should be formally signed – diverts attention from a more important question. In the short term, it is true that can Isis carry out guerrilla and terrorist attacks, but for all practical purposes Trump is right in saying that it has been decisively defeated. The caliphate that once ruled a de facto state the size of Great Britain with a population of eight million is gone.

A more important question to ask now is how far the whole al-Qaeda idea and mode of operating have become obsolete and discredited. Not so long ago, this militarised cult of extreme fanaticism with core beliefs derived from the Wahhabi version of Islam was extraordinarily successful. Suicide bombing on an industrial scale enabled it to turn untrained but committed believers into a devastating military weapon.

Suicide attacks as an expression of Islamic faith produced 9/11, which was the most successful terrorist attack in history: the overwhelming impact of the destruction of the Twin Towers provoked the US to jump into a trap of its own making by launching wars in Iraq and Afghanistan. Al-Qaeda, which had scarcely existed as an international organisation before 9/11, instantly took advantage of this overreaction. The US and British invasion of Iraq in 2003 enabled the local al-Qaeda franchise to became the core of the armed resistance of the Sunni Arabs against their enemies at home and abroad.

Can these conditions be recreated in Idlib or in the deserts of western Iraq, eastern Syria or wherever else al-Qaeda type groups have their hideouts from Pakistan to Nigeria and Chechnya to Somalia? A ferociously disciplined group with experienced military leaders will always have an influence out of proportion to its size in chaotic war-time conditions.

But al-Qaeda and its clones should not be allowed to remain a bugbear, a cause of obsessive fear because of its past successes in staging 9/11, dominating the armed opposition in Iraq in 2004-09, and unexpectedly resurrecting itself in Syria and Iraq after 2011.

It once was able to offer miraculous victories to its followers but for the past few years it has been able to offer them nothing but defeat and martyrdom for a cause that has been failing demonstrably.

The al-Qaeda formula worked because it caught its enemies by surprise and this will not happen again. Early successes after 2003 required a degree of covert assistance or tolerance from Syria, Turkey, Saudi Arabia and Qatar, all of whom imagined at different moments that they could channel or manipulate the jihadis into acting in their own interest.

Al-Qaeda operated through fear and fanaticism but it also required a constituency among the Sunni Arabs of Iraq and Syria which no longer exists; and for which the Sunni have paid a terrible price in the form of lost wars and devastated cities from east Aleppo to Raqqa and Mosul.

Al-Qaeda no longer works as a winning formula, but this does not mean that its destructive capacity is exhausted. Its track record of savagery was such that its limited attacks can still provoke almost unlimited terror among potential victims. I was in Baghdad last year when Isis kidnapped and killed some half dozen police on the main road north to Kirkuk, provoking a wave of fear out of proportion to what had happened among my friends who started to recall past massacres by Isis.

Casual remarks by Trump such as saying that the US might keep troops in Iraq in future to watch Iran will continue to keep the pot boiling which is to the advantage of al-Qaeda. But the all-conquering warrior cult whose columns of fanatical fighters were wining Napoleonic victories in 2014-15 has gone for good and cannot be recreated.