AACHEN – With the decision to withdraw from the Iran nuclear agreement – formally known as the Joint Comprehensive Plan of Action (JCPOA) – US President Donald Trump’s administration has demonstrated, yet again, that it is determined to destroy major global structures and agreements. The decision will be a massive blow to the 2015 deal, putting the entire world at risk. The JCPOA – the result of years of difficult negotiations – was agreed by seven countries and the European Union, and unanimously endorsed by the United Nations Security Council. Yet Trump has decided unilaterally to impose “the highest level of economic sanction” on Iran and on “any nation that helps Iran in its quest for nuclear weapons.” Now, companies and banks from countries that have lived up to their commitments under the JCPOA stand to suffer considerably, as a result of their legitimate business ties with Iran. In other words, the country that is breaking its promises has decided to punish those that have kept theirs. The JCPOA can still be salvaged. All of the other parties to the agreement have already reaffirmed their commitment to it. But the EU, in particular, must step up to take responsibility for ensuring that the JCPOA survives. While transatlantic relations are a high priority, so is defending multilateralism – and all of its milestones – from reckless and unjustifiable attacks. This is all the more true when those attacks aim not to put “America First,” but to put Trump first. Trump’s withdrawal from the JCPOA has come at a particularly sensitive moment for international relations. For one thing, nuclear proliferation remains at the top of the agenda on the Korean Peninsula. While some positive steps have lately been taken, the Trump administration, with its incoherent policy approach, may yet squander this opportunity. South Korean President Moon Jae-in recently met with North Korean leader Kim Jong-un to discuss a formal peace agreement to end the Korean War. The Moon-Kim meeting was a prelude to another extraordinary summit, between Kim and Trump, which will take place on June 12. The first-ever meeting between a North Korean leader and a sitting US President reflects the significant progress that has been made in the space of just a few months. Lest we forget, 2018 began with Kim and Trump exchanging threats for the umpteenth time, and with Trump going so far as to boast about the size of his “nuclear button.” Since then, however, the US has relied on diplomacy rather than bombast in handling the North Korean nuclear threat – an approach that has enabled recent progress. And yet, just as newly confirmed US Secretary of State Mike Pompeo was flying to North Korea to meet Kim for a second time, Trump reverted to his antagonistic modus operandi with regard to Iran. Negotiating with Kim was always going to be extremely challenging, especially given that North Korea, unlike Iran, already possesses nuclear weapons. With America’s diplomatic credibility now undermined by Trump’s violation of the JCPOA, that job will be all the more difficult. Indeed, when Mohammed bin Salman, Saudi Arabia’s crown Prince, visited the White House in March, Trump quickly dispensed with the thorny question of the Saudi-led war in Yemen by denouncing Iranian support for the Houthi rebels. Rather than take the diplomatic initiative to end the fighting and restore stability in Yemen, the Trump administration has continued to fan the flames of an ongoing Saudi-Iranian proxy war that is causing untold suffering and roiling the region. The current state of affairs does not bode well for the situation in Syria, where all of the region’s powers have a stake. Israeli and Iranian forces have already clashed in southern Syria, and Netanyahu’s government is now threatening further action in response to reports that Russia may furnish Syrian President Bashar al-Assad with S-300 anti-aircraft missiles. Trump’s abrogation of the JCPOA will almost certainly fuel the downward spiral of confrontation in the Middle East, while further complicating matters on the Korean Peninsula. More broadly, Trump’s decision could have serious implications for global nuclear nonproliferation efforts, which now face the prospect of backsliding. The stakes in the weeks and months to come could not be higher. The writer is President of the ESADE Center for Global Economy and Geopolitics, Distinguished Fellow at the Brookings Institution, and a member of the World Economic Forum’s Global Agenda Council on Europe. Copyright: Project Syndicate