Somewhere over the Atlantic, I’ve always suspected, there’s a giant glass curtain through which Americans view the Middle East – through a glass darkly, perhaps – and which utterly distorts their vision.

Even when they arrive in the region to chat to their “moderate” friends, the Sunni Muslim head-choppers, dictators and torturers who are now enlisting a mad American President in their alliance against Shia Muslims, the Western visitors do no more than mouth their propaganda and agree with Sunni Gulf plans to annihilate Iran.

It’s not just the Washington crackpot himself. Take General James “Mad Dog” Mattis, who is beginning to earn his sobriquet in his grasp of contemporary history, as well as the obscene comments which earned him his nickname during the illegal 2003 US invasion of Iraq.

Emerging from his meeting with the Saudis, whose Wahhabi faith arguably inspires the horrific Isis cult, the US defence secretary told American journalists that “everywhere you look, if there’s trouble in the region, you find Iran”.

Incredibly, no American reporter took Mattis up on this gobbledygook – which is odd, because we all thought Isis was the problem.

Isn’t Mattis aware that his men are helping the Iraqi army and pro-Iranian Shia militia destroy Isis in Mosul? Isn’t he aware that Isis – not Iran – have threatened to destroy the entire Western world? Does he not realise that Iran is the sworn enemy of Isis?

Nope? Well, there’s the “Mad Dog” for you. Iran is Shia Muslim; Isis is Sunni Muslim; Saudi Arabia is Sunni Muslim. Ring any bells?

But I guess that’s just too complicated for Trump’s warrior chief. So let’s take a long, hard, gritty look at the reality, which eludes the whole Trump menagerie.

Donald Trump says Iran has helped commit 'unspeakable crimes' in Syria

Let’s kick off with Syria, where (according to Saudi Arabia, the United States and Israel and most of the pseudo-experts on Western television) Iran is in the process of taking control.

A reality check: most of the Syrians I meet in Assad regime-controlled territory: in Damascus, Homs, Hama and Aleppo, and a lot of the Syrian army, were grateful for Russia’s intervention – not just because it reversed the grave defeats of the government military forces, but because it counterbalanced Iran’s influence in their country.

Officially, the ruthless Syrian army counts Russia, Iran and the Hezbollah as its allies, which is why their flags fly together outside military headquarters in some Syrian cities.

But Syrian soldiers were not impressed by the few thousand Iranian forces – not 30,000, as the New York television mountebanks claim – who arrived to help them. Relations became even more fraught when Iran claimed that its forces had participated in the capture of eastern Aleppo last winter.

It was a lie. The Iranians invented this fact as surely as Trump invents facts in the Middle East. And the Syrians bitterly resented this dishonesty.

No Iranian forces took part in the December east Aleppo battles – despite what Tehran boasted – that almost at once led to allegations of rape carried out by Syria’s allies.

The rape claims were then directed at Iraqi Shia militias – which also, according to civilians in Aleppo (from both east and west), were not present in the battle.

In fact, Syrian troops whose families and homes were in eastern Aleppo were deliberately included in the attacking forces because they knew the roads and buildings. It’s unlikely they would have permitted Iranian or Iraqi or any other militias to have raped or mistreated their families.

There may well have been executions during the fighting (a war crime, make no mistake about it), but the “rape” of eastern Aleppo was a gross exaggeration, despite Iran’s lie which helped to spawn such stories in the first place.

Then there is the story, put about by Washington, that the Syrians and their Russian allies and the Iranians only fight the American-paid “moderate” – and largely mythical – opposition forces, and do not go into combat against al-Qaeda, Jabhat al Nusrah or Isis. This is nonsense.

I’ve been on the front lines when the Syrians were fighting Nusrah and al-Qaeda south of the Turkish frontier and north of Lattakia.

In a later struggle at the very same positions, all but one of the Syrian soldiers I interviewed (almost all of them Sunni Muslims, although we are supposed to believe that they are, like their president, Shia Alawites) were killed in a massive suicide bombing by Nusrah.

South of Qamishleh and in Palmyra and, most recently, east of Aleppo, I have seen Syrian troops in direct combat with Isis. When they recaptured Deir Hafer, 20 miles east of Aleppo, in April, I entered the town with the first Syrian soldiers. Isis had just fled for their lives under shellfire and air attack, leaving their infamous black flags, crucifixion posts, arms factories and black-painted Islamic courtrooms still intact.

And yet Washington still maintains that the Syrians don’t fight Isis.

Aleppo before the Syrian Civil War Show all 12 1 /12 Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man crosses a street in Aleppo, December 12, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A vendor sits inside an antique shop in al-Jdeideh neighbourhood, in the Old City of Aleppo, December 12, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A view shows part of Aleppo's historic citadel, overlooking Aleppo city, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A view shows part of Aleppo's historic citadel, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Visitors walk inside Aleppo's Umayyad mosque, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk inside the Khan al-Shounah market, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man walks past shops in al-Jdeideh neighbourhood, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk along an alley in al-Jdeideh neighbourhood, in the Old City of Aleppo, Syria Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War Visitors tour Aleppo's historic citadel, Syria December 11, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A general view shows the Old City of Aleppo as seen from Aleppo's historic citadel, Syria December 11, 2009 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War People walk near Aleppo's Bab al-Faraj Clock Tower, Syria October 6, 2010 Reuters Aleppo before the Syrian Civil War Aleppo before the Syrian Civil War A man stands inside Aleppo's historic citadel, overlooking Aleppo city, Syria December 11, 2009 Reuters

Indeed, when the Americans observed the pro-Assad Iraqi Shia militias and Iranians heading for the south-west border town of al Tanf, where the Jordanian, Iraqi and Syrian frontiers virtually bisect each other, they bombed the pro-government forces – not the Isis cultists further north.

Because cutting off Iran’s highway to Syria via Iraq was more important than the war against Isis. Which is why Mattis is sending more weapons to the Kurds, who are expected to fight ISIS around Raqqa, on America’s behalf.

Then there is Lebanon, which US ‘experts’ now claim to be Iranian-controlled territory – because this is where Hezbollah come from and because (though they don’t say this) the Lebanese Shia are the largest individual community in Lebanon, albeit not a majority of the population.

Which leads us to the untold story – largely unreported in the West, of course – of how Saudi Arabia declined to issue an invitation to the Lebanese president, a Christian, to attend the Muslim-Trump summit in Riyadh. Of all the Middle East Arab nations, Lebanon was the only country whose president was not invited. Because he was a Christian? Or because he supports Hezbollah and – up to a point – the Syrian government?

Needless to say, the Lebanese Prime Minister, Saad Hariri – a Sunni Muslim, of course, and by quaint coincidence a Saudi citizen too – was asked to represent Lebanon in Saudi Arabia.

Now Hezbollah clearly does rule parts of southern Lebanon and the north Bekaa Valley. They are a militia. They do not represent Lebanon, although their armed presence is tolerated more, one suspects, because the Shia population is now so large that it could, if it wished, claim more seats in parliament. In which case, who would want an Islamic Republic in Lebanon?

In theory, the United Nations controls the southern rim of Lebanon opposite the Israeli frontier, but this in itself is a doubtful assertion. Hezbollah, armed and paid by Iran, recently took journalists on a trip through the UN zone. And just north of the Israeli frontier is an area known to the UN as “the Iranian gardens” in which UN soldiers do not patrol. Ask the UN about it.

So Iran is present via its Lebanese proxies in Lebanon. Besides, although Hezbollah has elected ministers in the Lebanese government, they do not represent a majority amid their Christian, Sunni and Druze parliamentary colleagues.

Yet oddly enough, Lebanon is key to the crazed arguments of Mattis and his colleagues, including ex-marines who served with him in Iraq – where the Americans were constantly (but without proof) claiming that Iran was arming the opposition to US occupation. They even arrested Iranian diplomats in Iraq as terror suspects, before quietly releasing them.

Art exhibition in Lebanon shut down by people trying to erase imperialism from their history

Colonel Timothy Geraghty, the US marine colonel who was in command of the military base in Beirut when it was blown up by a suicide bomber in 1983 – 241 US servicemen lost their lives – is still today lecturing about the evils of Iran.

In 1983, the Americans were demanding a Lebanese peace treaty with their Israeli allies and Iran saw that this would end all Shia resistance to Israel in Lebanon. And there is no doubt that Iran was involved in the bombing. But that was more than three decades ago.

In 1983, the Americans were supporting the evil “Hitler of the Tigris” Saddam Hussein in his war against Iran – and in 1983, the West was still preparing for a Soviet invasion of Western Europe. Yet still Trump’s warriors beat the drums of war against what Israel calls the “Iranian octopus”. Generals traditionally want to fight old enemies rather than new ones.

Obama fired Mattis because he was so obsessed with Iran. But now Trump supports a Sunni war against the Shia, and Mattis is back to fight his old battles all over again.