Once again Iran is the focus of attention for Washington’s foreign policy hawks – and by extension for the rest of us. Donald Trump says he doesn’t want a war with Iran, but his national security adviser, John Bolton, has despatched warships and bombers to the region while the US secretary of state Mike Pompeo has been sharing worrying intelligence about Iranian intentions with close allies and congressional leaders.

What’s going on? It’s now a year since Trump tore up the nuclear deal with Iran negotiated in 2015 by the Obama administration along with Britain, France, Germany, Russia, China and the EU. Since then, egged on by Israel and the Gulf states, he has announced new sanctions, despite Iran’s full compliance with the terms of the deal, and tried bullying the Europeans and others into applying US sanctions in order to deny Iranians the economic benefits they were promised.

Iran hits back at Trump for tweeting 'genocidal taunts' Read more

After a year of waiting to see if the other signatories would make the deal work without US cooperation, the Iranians announced earlier this month that they would no longer fully comply with the uranium and heavy water restrictions of the agreement – and that, unless the Europeans could help with oil and banking within 60 days, more drastic measures would follow. Western governments sometimes forget that the Iranian government is not a monolithic entity, and that the officials they are used to dealing with, such as president Hassan Rouhani and foreign minister Javad Zarif, are under constant pressure from hardliners who point to the lack of any return on the investment Iran made four years ago.

Since Trump pulled the plug, the Europeans have been working on a scheme to allow some forms of trade with Iran to continue independently of the US. Its effects have been limited, leading the supreme leader, Ali Khamenei, to convince himself – wrongly – that the Europeans were only ever playing good cop to Washington’s bad cop. As US sanctions continue to damage the Iranian economy, Trump says he is still interested in some kind of grand bargain. Tehran should call me, the president says, perhaps not realising that there would be huge political consequences for anyone who did.

Facebook Twitter Pinterest An anti-US rally in Tehran, in support of Iran’s decision to pull out from the nuclear deal. Photograph: Abedin Taherkenareh/EPA

But outside the US, the impression has grown that the hawks in the Trump administration are more interested in regime change than in policy change – and by military action if necessary. There are shades here of Iraq 2003, when the George W Bush administration was desperate to prove that Saddam Hussein had weapons of mass destruction. It is nonsense to claim, as Pompeo did last month, that “there is a connection between the Islamic Republic of Iran and al-Qaida. Period. Full stop”. Al-Qaida’s roots are in Sunni, Wahhabist Saudi Arabia, and it hates Shia Iran almost as much as it hates the US and its allies.

The Europeans have never disagreed about the nature or extent of Iran’s destabilising activity in the region. But they don’t buy the regime change argument, knowing from experience that outside pressure is more likely to strengthen rather than weaken the hardliners. They also still believe that the best way to prevent Iran acquiring nuclear weapons is to stick with the deal.

There is now a real risk of the world finding itself with another Middle Eastern conflict on its hands, by accident or miscalculation. What can be done? As many of us have been saying to Iranian officials for some time, they should help others to stand up for the nuclear deal by moderating Iran’s behaviour in the region: stop supplying sophisticated weaponry to Hezbollah in Lebanon; and stop supplying missiles to the Houthi militia in Yemen that perpetuate the horrific civil war. Iran could use its influence over President Bashar al-Assad to press him to avoid further bloodshed in Syria. And it could end the imprisonment and abuse of dual nationals and other Iranian citizens on specious grounds.

Some suggest that current tensions may be partly the result of misunderstandings between Tehran and Washington. That wouldn’t be surprising, given the long history of distrust and the absence of diplomatic relations between the two countries for 40 years. But it serves as a reminder that some form of direct communication is essential: both sides should move quickly to activate private channels.

Old grudges, new weapons… is the US on the brink of war with Iran? Read more

Back in 1987 – when the UN security council was trying to stop the Iran-Iraq war Saddam had started (with western encouragement) seven years earlier – the council passed a resolution calling for an immediate ceasefire and a withdrawal to international borders. It didn’t manage to stop Saddam launching another, ultimately unsuccessful offensive. But tucked away in paragraph eight was a request to the secretary general “to examine, in consultation with Iran and Iraq and with other states in the region, measures to enhance the security of the region”.

That resolution is still valid. Why not look again at the idea of all the regional powers, under UN auspices, coming together with a view to lowering tensions? A recent OpEd in the New York Times by Abdulaziz Sager, a Saudi Arabian academic, and Hussein Moussavian, a former Iranian nuclear negotiator, argues that the time for the region’s two big rivals to sit down and try to bury the hatchet might just might have come. So much is at stake that it’s surely worth a try.

• Peter Westmacott is a former British ambassador to the US