The deep divisions between US and its European allies over how to handle the Iran issue have been brutally exposed by their differing responses to the assassination of Qassem Suleimani. Ever since US President Donald Trump announced in 2018 that he was withdrawing Washington from the nuclear deal signed between Iran and six of the world’s leading powers in 2015, tensions have been building between the US and the Europeans over their respective approaches to Tehran. While Washington has embarked on a policy of applying what it calls “maximum pressure” against Tehran, primarily in the form of imposing harsh economic sanctions, the European signatories to the deal – Britain, France and Germany – have continued to maintain their support for it, arguing that it is the best means of delaying Tehran’s attempts to develop a nuclear weapons arsenal. Certainly, the crisis that has erupted over the Trump administration’s unilateral action in assassinating Suleimani near the Baghdad airport last week would have been immeasurably more alarming had Tehran succeeded in its goal of developing nuclear weapons. But the main criticism voiced by the Europeans was less concerned with the fate of the nuclear deal than it was with the wider security implications of the American actions. France, where President Emmanuel Macron has been spearheading a valiant effort to persuade Tehran to re-enter negotiations, was first to condemn the attacks. Amelie de Montchalin, France’s Europe minister, declared that the attack had made the world “more dangerous" and that Paris would focus its efforts on de-escalating in the Middle East. It was a similar picture in Germany, where the government of Chancellor Angela Merkel warned that the American action had created a dangerous escalation in tensions. About the only European power that gave a more nuanced response was Britain where, after initial calls for restraint, Prime Minister Boris Johnson pointed out that Suleimani had “the blood of British troops on his hands” having been responsible for the deaths of forces serving in southern Iraq, and that he would “not lament” the death of Iran’s terrorist mastermind. Yet speaking to fellow Members of Parliament shortly afterwards, Mr Johnson also made it clear that Britain remained committed to saving the nuclear deal as the best means of limiting Iran’s ambitions. He also made a phone call to Hassan Rouhani, the Iranian president, today to reaffirm his commitment to the deal. The lukewarm response from Britain and other European allies after Washington’s action against Suleimani, whom the Americans insist was in the process of plotting a further series of attacks against US diplomatic and military personnel in the region, has clearly angered Mr Trump. He criticised Britain and the rest of Europe for continuing to back what he called the “defective” nuclear deal with Iran. “The time has come for the United Kingdom, Germany, France, China and Russia to recognise this reality. They must now break away from the remnants of the Iran deal,” he said. This is unlikely in the case of Russia and China, which – together with the US – make up the other signatories to the deal. Both Moscow and Beijing regard their continuing support for Iran as presenting a useful means of countering Washington’s traditionally dominant position in the region, with Russian and Chinese warships recently taking the unprecedented action of joining Iran in conducting naval patrols in the Gulf. For America, though, the positions of the Europeans are more problematic because, at a time when Washington’s primary focus is dealing with the threat posed by emerging powers such as China and Russia, it is keen to maintain the semblance of unity in the western alliance, rather than having to contend with significant policy differences. The challenge now, therefore, is for the US and Europe to find a way of settling their differences before irreparable harm befalls an alliance that has made a major contribution to maintaining global security for the better part of 70 years. One factor that may help matters is Iran’s announcement in the immediate aftermath of Suleimani’s assassination that it would no longer abide by any of the limits of imposed on its nuclear activities by the deal. By abandoning the accord’s key provisions that block Tehran from having enough material to build an atomic weapon, the Iranians are sending their clearest signal yet of their intent to resume work on their weapons programme. If Iran continues to violate the deal in this manner, then the agreement is, in effect, null and void, and the Europeans are off the hook in terms of having to maintain their token support for an agreement which, without US participation, has little validity anyway. Another area where Europe can provide the US with tangible support is in the field of military and security cooperation. The Iranian threat, so far as its confrontation with the West is concerned, is not just directed at the US. European powers, too, can just as easily be targeted by Iran’s increasingly sophisticated ballistic missile systems, as well as its terrorist infrastructure. In recent months, Tehran has been accused of carrying out terrorist operations in Copenhagen, Paris and Berlin, an indication the terrorist operations once overseen by Suleimani were by no means confined to the Middle East. This week’s announcement by Nato Secretary-General Jens Stoltenberg that the 29-member alliance will play a greater role in the Middle East is certainly a step in the right direction. For Iran will be the only country that will benefit if divisions continue within the western alliance. <em>Con Coughlin is the Telegraph’s defence and foreign affairs editor</em>