There goes the president’s Nobel Peace Prize, then. Far from the most important aspect of Donald Trump’s decision to scrap the Iran nuclear deal is that whatever credit he might have accrued for pushing North Korea towards peace talks and denuclearisation is entirely negated by his reckless decision to disengage with Iran. However, it does serve to put the true nature of American foreign policy in the right perspective.

The fact that the break with Iran was no surprise and a long time coming, indeed fulfilling a promise kept from his maverick (and reckless) election campaign, does not make the damage done to ever-more fragile hopes of peace in the Middle East any less grievous. Nothing, it seems, is allowed to get in the way of The Donald’s childish mission to undo – just for the sake of undoing – everything that his predecessor achieved in office.

Barack Obama, dignified as ever, made an exception to his usual patient silence with a withering condemnation of this latest initiative. Maybe that’s precisely what The Donald was hankering after. As has been often remarked, it is like having a big baby in the White House – and the most dangerous, spiteful, impulsive, peevish, unthinking, unstable baby on Earth.

Contrast the fortunes of the Democratic People’s Republic of Korea and the Islamic Republic of Iran. Where once both were linked, famously, by George W Bush in the “axis of evil”, one is about to be courted by Mr Trump, the other ostracised and bullied, placed in the odd position of appearing a victim (for Iran has to answer for its own share of aggressive acts, sponsorship of terror and violations of human rights).

Iran parliament reacts after Trump's withdrawal from nuclear deal Show all 10 1 /10 Iran parliament reacts after Trump's withdrawal from nuclear deal Iran parliament reacts after Trump's withdrawal from nuclear deal Iranian MPs burnt a US flag in parliament after Donald Trump announced America's withdrawal from the nuclear deal. AFP/Islamic Consultative Assembly News Agency Iran parliament reacts after Trump's withdrawal from nuclear deal US President Donald Trump displays a presidential memorandum after announcing his intent to withdraw from the JCPOA Iran nuclear agreement in the Diplomatic Room at the White House. Reuters Iran parliament reacts after Trump's withdrawal from nuclear deal Some Iranian MPs reacted after Trumps decision by shouting 'death to America'. AFP/Islamic Consultative Assembly News Agency Iran parliament reacts after Trump's withdrawal from nuclear deal Iranian lawmakers prepare to burn two pieces of papers representing the US flag and the nuclear deal. AP Iran parliament reacts after Trump's withdrawal from nuclear deal Iran said it will hold talks with signatories to the nuclear deal after Trump's decision to withdraw from the accord, which it branded "psychological warfare". AFP/Islamic Consultative Assembly News Agency Iran parliament reacts after Trump's withdrawal from nuclear deal Several Iranian MPs stood chanting in the Tehran parliament. AFP/Islamic Consultative Assembly News Agency Iran parliament reacts after Trump's withdrawal from nuclear deal Iranian MPs burning a US flag AFP/Islamic Consultative Assembly News Agency Iran parliament reacts after Trump's withdrawal from nuclear deal President Hassan Rouhani addressed the nation in a televised speech in Tehran. He said he'd send his foreign minister to negotiate with countries remaining in the nuclear deal after Trump's decision to pull America from the deal, warning he otherwise would restart enriching uranium "in the next weeks." Iranian Presidency Office via AP Iran parliament reacts after Trump's withdrawal from nuclear deal Iran's press condemned Trump's withdrawal from a multi-party nuclear deal but was divided over whether Tehran should react with patience or withdraw itself. AFP Iran parliament reacts after Trump's withdrawal from nuclear deal Trump announced the US withdrawal from what he called the "defective" multinational nuclear deal with Iran, and said Washington would reinstate sanctions against the Islamic republic. AFP/Getty

What conclusion should the civilian and the theocratic wings of the regime in Tehran draw for the contrasting treatment affecting the old “axis of evil”? Simply that for America to treat you with respect you had best arm yourself with nuclear missiles – and the longer the range and the more high profile the tests the better. That is just what North Korea did – with Mr Trump making empty threats about “fire and fury”.

Iran now has little to lose, as it has itself put it, from developing nuclear weapons “on an industrial scale”. Israel has already done so, scarcely pretending otherwise. In defiance of the very same international rules as Iran will flout, America seems content with Israel enjoying the – so far – overwhelming strategic advantage of the sole possession of weapons of mass destruction in the region. No surprise, then, that President Trump has at last acceded to lobbying to accept Jerusalem as Israel’s capital, de facto. It is precisely because Israel is believed to be equipped with nuclear weapons, and because Israel has shown itself more than willing to act as an American proxy in Syria, including attacking Iranian-backed militias, that Tehran has the incentive to develop its own “deterrent”.

Saudi Arabia has found itself in the same camp as Israel thanks to America’s crude policy of taking sides in the nexus of proxy conflicts in the region, an uncomfortable pairing – and Saudi Arabia too could develop weapons of mass destruction. Turkey might harbour a similar ambition, if its neighbours do, and not so very far away we find an expansionist and interfering nuclear Russia, looking always for an opportunity to extend its power and influence, regardless of human cost (to some other people). Hence the survival of Assad, despite everything. The Joint Comprehensive Plan of Action (JCPOA) may not have ended the nightmare of regional nuclear proliferation, but scrapping it will make it more certain.

Horrifyingly, the Middle East will now be propelled into its own nuclear missile race, each regional power wishing to find a patron superpower – Russia or America – happy to oblige with diplomatic and military back up. Rather than attack one another directly (yet), America, Russia, Saudi Arabia, Israel and Turkey then – as we have witnessed across the great arc of conflict that spreads from Libya to the borders of Pakistan – play out their pitiless wars through others, bombing, maiming, gassing and terrorising numberless Syrians, Yeminis or Iraqis unlucky enough to find themselves this year’s proxy battlefield of choice. Sometimes they informally back Isis, sometimes some other death cult; it hardly seems to matter.

EU remains committed to Iran nuclear deal despite US withdrawal says Federica Mogherin

We have seen too much of all that, and, emboldened by Mr Trump’s disastrous initiative, we will no doubt witness much more, including in Lebanon before long – and with it the floods of humanity seeking refuge.

“If we do nothing we know exactly what will happen”, Mr Trump told the world. Debatable, at best, because the JCPOA, had its flaws but it was working – it was restraining Iran and giving its more moderate civilian leadership something to show the ayatollahs for the policy of engagement with the West. The hardliners in Tehran and Qom – led by the old-school supreme leader Ayatollah Khamenei, in power since 1989 – will feel themselves vindicated by Mr Trump’s breach of trust. Cue the burning of American flags and poorly-constructed effigies of President Trump.

Always disinclined to trust the West, it is difficult to see why Iran should pay much attention to the Great Satan in future, sanctions or not, and dial down the terror. Kim Jong-un has demonstrated the way to get America to play ball; get you some nukes. Meantime, Iran can further cement its alliances with Russia and Turkey, with consequences bloodily familiar to the citizens of Aleppo and Douma.

One of the other bitter ironies in this huge Trump gamble is that the sanctions and attendant chaos will hurt American interests – security and economic – rather more than Iran’s. America’s sanctions will not, this time, be adopted by her European allies, let alone China or Russia, while the current panic-driven spike in the price of oil will actually benefit Iran, as a major producer.

France, Germany, Japan, South Korea, Britain and the rest will continue to trade and invest in Iran; unless, that is, Mr Trump wants to draw the ambit of sanctions so wide that America will seek to punish the likes of Peugeot, Siemens and Hyundai-Kia just as he is, pointlessly, going to take billions of dollars’ worth of business away from Boeing, Coca-Cola and others. Ironically, again, North Korea might well continue, clandestinely, to assist Iran with its nuclear weapons programme just as it is winding its own down.

In other words, even on its own terms, Mr Trump’s policy of all-out unilateral economic warfare makes no sense, because it is so counterproductive. Even if it did work, after a fashion, what if Iran, far less isolated than North Korea, and far richer, just ploughs on? Will America, or Israel, or even Saudi Arabia, bomb Iranian military or nuclear installations in breach of sense and international law? If not – then what?

America’s allies, too, have been betrayed. The joint communique by Emmanuel Macron, Theresa May and Angela Merkel notes their “regret” at Mr Trump’s decision. That is some understatement. They also “regretted” his withdrawal from the Paris climate treaty, the new American embassy in Jerusalem, the trade wars with China, Japan and the EU, insults tweeted at London and Paris and much else.