Remarks this week about Iran by US National Security Adviser John Bolton contained some of the most ferocious language ever used by an American administration about a foreign state. Bolton told the Iranian regime: “If you cross us, our allies or our partners; if you harm our citizens; if you continue to lie, cheat and deceive, yes, there will indeed be hell to pay. Let my message today be clear: ‘We are watching, and we will come after you.’”Earlier this year the US pulled out of the nuclear deal with Iran, re-instituting potentially crippling sanctions against the regime. At the UN, President Trump delivered a similar message. America, he said, would not allow “the world’s leading sponsor of terrorism” to possess “the means to deliver a nuclear warhead to any city on Earth.”Bolton went further and threatened “terrible consequences” for those doing business with Iran. But Britain and Europe are intending to do exactly that. Earlier in the week, the EU and the three European co-signers of the Iran deal – Britain, France and Germany – said they would set up a new payment system to allow oil companies and businesses to continue trading without relying on the US-led global market. Commentators agree this sanctions-busting ruse is unlikely to work. Big companies are already pulling out of Iran because the US says they can trade with Iran or America but they can’t do both. The European maneuver is likely merely to antagonize the US. As its Secretary of State Mike Pompeo angrily said, the Europeans were now “solidifying Iran’s ranking as number-one state sponsor of terror” with “one of the most counterproductive measures imaginable for regional peace and security”.So why are the Europeans hell-bent on propping up Iran and the wretched nuclear deal? Economic self-interest is an important factor, but it’s not the only one.The Obama administration and the deal’s other sponsors con- vinced themselves that the agreement would tame the Iranian regime, strengthen Iran’s supposedly “moderate” President Rouhani against hard-liners, and somehow defuse Iran’s nuclear weapons threat. This last assumption – repeated this week by Britain’s Prime Minister Theresa May – was the most baffling, since the deal’s “sunset clause” would enable Iran to break out into nuclear weaponry after some 15 years or so. The deal’s backers also ignored key facts, such as that the only person who matters in Iran isn’t Rouhani but the supreme leader, and that lifting sanctions would enable the world’s most lethal terrorist state to ratchet up its murderous assaults and regional power.In other words, to avoid taking a decision with difficult conse- quences the deal’s backers convinced themselves that black was white. Such mental contortionism is typical of the mentality of appease- ment. And that happens to be producing a particular echo right now. For this Sunday sees the 80th anniversary of the infamous Munich agreement, the deal signed by Britain, France, Italy and Germany that permitted Hitler’s annexation of the Sudetenland in Western Czechoslovakia. When the British prime minister Neville Chamberlain returned from Munich and waved this agreement in front of wildly cheering crowds, the received wisdom was that this had averted war. One year later, Britain declared war on Nazi Germany.There were two main reasons for Britain’s appeasement mental- ity in the thirties. The first was the profound national trauma inflicted on the country by the First World War.The terrible carnage in the trenches wiped out virtually an entire generation of the brightest and best. It changed Britain forever; it damaged its religious faith and its confidence in the future; it destroyed its belief in Western civilization and in itself. The war was viewed as senseless slaughter. This post-traumatic war phobia was amplified by a chronic pessimism about Britain itself. In the late twenties and early thirties, Britain was struggling with economic depression. The Empire was beginning to fall apart with uprisings in India and Palestine, while Britain was losing out to the expansion of Italy, Germany and Japan.So, most of the support for appeasement came from a perception (however misguided) of the national interest.Starting from the premise that simply anything was better than war, the appeasers proceeded to construct arguments to justify it. They told themselves that once Hitler’s territorial designs over Czechoslovakia were met, his aggression would diminish. Several even convinced themselves that Germany was entitled to rule the Sudetenland.But their premise was wrong. Appeasement didn’t prevent war; it merely made an always inevitable war even more terrible.This is why the appeasement of Iran is so terribly wrong. The regime should be fought and defeated by any means possible.A recent seminar on the Munich agreement at the Jerusalem Center for Public Affairs heard from National Infrastructure, Energy and Water Minister Yuval Steinitz, who was Israel’s chief negotiator during the Iran deal negotiations. He observed that even if the US is forced to operate Iranian sanctions alone, it can exert greater economic pressure than can the rest of the world. That’s not just because of the sanctions themselves but also, crucially, because of the secondary sanctions the US will impose against those who try to evade them.The Iranian rial is already in free-fall. One year from now, predict- ed Steinitz, Iran’s economic situation will be dire. Maybe the regime will be forced back to the negotiating table; or maybe it will go for broke and accelerate its nuclear weapons program. If it were thus to step-up uranium enrichment or restart its mothballed centrifuges, he said, the US would unleash military strikes against it. Even if Iran has buried its nuclear infrastructure underground, he said, no such facility in the world is immune to air attacks.And the regime knows it – which is why it is so desperate to keep the nuclear deal in existence. Without it the regime’s options are extremely limited; which is why the European attempt to keep rewarding Iran as if the deal still existed is such a blow against world peace.At the UN, Trump was laughed at mockingly when said he had already been an effective president. Yet he has weakened the world’s principal genocidal terrorist state – while Britain and Europe, hav - ing empowered it, are now trying to strengthen it still further. Trump may make some people laugh at him; but the appeasement of evil by Britain and Europe should make us cry.The writer is a columnist for The Times (UK).