THE alliance that defeated the militant Islamic State group in Mosul was unusual. Fighting alongside the Iraqi army were not only US forces but also Iran-backed militias. A few weeks ago, with IS on the point of defeat, I spoke to a US officer in Baghdad and suggested he might want to praise Tehran for having stood shoulder to shoulder with Washington in such an important military effort. He declined the offer.

America’s loathing of the Iranian clerical regime knows few bounds. In March 2003, the US desperately needed to understand the strength of Al Qaeda in Iraq. Having invaded the country and initially swept through it, the occupying US forces soon came to fear that an insurgency was getting under way. They needed to know the extent to which Al Qaeda was the source of that opposition. After all, 9/11 was still fresh in the memory and Al Qaeda was US enemy number one.

State Department official Ryan Crocker, accompanied by president Bush’s special envoy to Afghanistan, Zalmay Khalilzad, approached Tehran. The US diplomats were aware that, in the immediate aftermath of 9/11, some senior Al Qaeda operatives and some of Osama bin Laden’s relatives had found a safe haven in Iran.

Iran made a unique offer. The US turned it down.

Tehran’s motives for taking in these Sunni jihadists and giving them sanctuary remain unclear but it seems likely that one factor in the decision to accept them was the idea that Tehran would have a diplomatic card to be played at some date in the future. And with the US showing an interest, Tehran figured the time to play that card had come.

Iran made an extraordinary offer: if the US would hand over the leaders of an obscure Iraq-based cult called the People’s Mujahideen of Iran or Mujahideen-i-Khalq (MEK), that opposed the Iranian government, Tehran would give the US most of Al Qaeda’s military council and bin Laden’s family. Astonishingly, the Bush White House turned down that opportunity.

The story of the MEK itself illustrates the depth of the US hostility to Iran. At the time of the Iranian revolution, the MEK tried to combine Islamic revolutionary fervour with a leftish and feminist agenda that attracted support on the university campuses. Although the group denies it, there is overwhelming evidence that it had killed Americans before the revolution and was fully involved in the 1979 siege of the US embassy. Despite that history, Washington has subsequently come to embrace the MEK as a potential source of opposition to the clerical regime.

In 2012, Hillary Clinton gave into a very well-financed lobbying campaign and officially delisted the MEK as a terrorist organisation. As a result, the organisation now has an office in Washington. At a recent party conference in Paris, the MEK attracted American luminaries such as Rudy Guliani and former senator Joe Lieberman.

I once asked a serving member of the US Senate, who did not support the MEK and who was known for his deep knowledge of the Middle East, to explain why so many his colleagues backed the organisation. “Beats me,” he said. “Sometimes colleagues ask my advice, saying they have been approached by the MEK and want to know whether they should support them.”

“And what do you say?” I asked.

“I say that since the MEK killed Americans there is always a risk of a voter asking why their senator is backing a group that killed their relative. You have to be careful of that kind of thing.”

“And does that put them off?”

“Sometimes.”

For all the mutual vitriol between Iran and the US, a case can be made that Iran’s Shia Islamists could be more natural allies of the US than the Sunni states that sponsor violent jihadists. On the few occasions that their views are revealed, many young Iranians show that despite having absorbed a lifetime of propaganda about the Great Satan they remain attracted by Western values. Many Sunni youths in the Middle East have far greater distrust of the West than their Shia equivalents. It is no accident that the 9/11 attackers came not from Iran, but from Sunni states.

For many years, it was argued that the US hostility to Iran could be traced back to the US embassy siege of 1979. The humiliation suffered by the US at that time was keenly felt and left a deep mark. Yet the US has got over far greater humiliations — for example, at the hands of the North Vietnamese. Today, US presidents are quite comfortable visiting Hanoi despite what happened there. The difference, perhaps, relates to Israel. Ever since the destruction of Iraq, Prime Minister Netanyahu has made no secret of his view that Iran now poses the most significant threat to the state of Israel. By continuing to oppose Iran, the US is supporting its closest ally.

The writer is a British journalist and author of Pakistan: Eye of the Storm.

Published in Dawn, July 27th, 2017