Relief at Iran’s significant but calibrated retaliation against the US for the killing of Qassem Suleimani is an understandable and merited instinct. Matters could be much worse today. But there can be no complacency: the dangers have been briefly stayed, not averted. While Donald Trump said on Wednesday that Iran “appears to be standing down”, we will not know the true impact of the killing for months and probably years.

The strikes on Iraqi bases hosting US and coalition troops constituted Iran’s most direct attack on Americans since the seizing of the US embassy in Tehran in 1979, and the first direct assault on a US base. This was a bold and symbolic display: an operation timed to match the moment of the general’s death. But it was also limited. Despite Iranian claims of 80 casualties, the US says no Americans were hurt. The Iraqi prime minister, Adel Abdul-Mahdi, has said the Iranians warned him of their actions just ahead of the attack. The Iranian foreign minister, Mohammad Javad Zarif, stated on Twitter that his country had concluded its response and that “we do not seek escalation or war”.

Given that Iran cannot afford a hot war, Wednesday morning’s strikes look like a sensible response, but hardly the “severe revenge” it had vowed. The supreme leader, Ayatollah Ali Khamenei, has described them as a slap in America’s face, which cannot compensate for the assassination: “What is important is the ending of American presence.” Whether or not a US withdrawal from Iraq is imminent, the events of the last week have surely made it almost inevitable. That might be enough to assuage Iran’s damaged pride, allowing it to say it has – as Suleimani long wanted – chased out the US, which will be left without even a fig leaf of any achievement to show for its disastrous 2003 invasion.

But the missile attacks also allow Iran to return to its favoured mode of plausible deniability, relying on proxies, cyber-attacks and terrorism. We could see attacks on US military personnel and civilians in the region; on the oil infrastructure of regional partners; attacks against Israel from Syria. The reverberations could be felt in Afghanistan. Americans might be targeted much further afield.

Suleimani’s killing impels Iran to hit back hard – even as it is more aware than ever of the volatility and ignorance of the US commander-in-chief, and the influence of the administration’s Iran hawks. The events of the last week have made it even clearer that Mr Trump has no Iran strategy; just a bundle of impulses and prejudices. His suggestion that Nato should be more involved in the Middle East merely added to the confusion. He is also desperate to distract from his impeachment trial and to win another term this November. In his pre-White House days, Mr Trump repeatedly warned that Barack Obama might start a war with Iran to get re-elected.

Instead, of course, Mr Obama achieved the nuclear deal which Mr Trump has done his best to destroy. The JCPOA blocked Tehran’s progress towards nuclear weapons. On Wednesday the president suggested that the UK and others should help him to win a better deal. This would be ludicrous even if his administration had a genuine interest in such an agreement or the capacity to negotiate it. By withdrawing the US and turning up the pressure on Iran, he has told Tehran and others that the US is utterly unreliable and (as George W Bush’s did by invading Iraq) that getting and keeping weapons of mass destruction is the key to survival. Whatever the short-term outcome of this crisis, the long-term implications for peace are obvious, and frightening.