In diplomacy, there is an unwritten rule that states that when an agreement on a particular matter stagnates, it is time to broaden the conversation surrounding that matter. Now, the U.S. appears to be prepared to reverse this maxim in order to shoot down a deal that is already in place. And not just any deal, but the nuclear deal with Iran, one of the greatest diplomatic achievements of the past decade, despite Donald Trump describing it as a “disgrace” in his speech before the United Nations General Assembly. Iran has always been a tough negotiator. An infinite number of forces and personalities converge in its distribution of power, which often contradict or rival one another. This hinders the interpretation, and even more so the control, of the course of the negotiation.

As things stand at the moment, reaching a “meta-deal” with Iran that encompasses all of its affronts to international order − not only its nuclear and missile programs, but also its support of international terrorism, regional destabilization and human rights violations − seems illusory. In order to succeed, it is necessary to narrow down and limit the objective of the negotiations as much as possible.

This was the focus of the discussions on the Iranian nuclear program, which culminated in the Joint Comprehensive Plan of Action. Its name is somewhat distant from its content, however, as it does not cover issues related to nuclear armament programs, nor does it guarantee inspections at military facilities, and the majority of its regulations will only be valid for a period of 10 years. The JCPOA did not aspire to cover every issue, but rather to temporarily neutralize the existential threat posed by the Iranian nuclear program and to establish the foundations of a constructive agreement that will lead to progress on other fronts. The deal marked a beginning, not an end.

However, it is possible that the diplomatic door that JPCOA opened is about to be slammed shut. In accordance with U.S. legislation, the president must confirm before Congress every 90 days that Iran is complying with the deal and that the continuing suspension of sanctions is “vital to the national security interests” of the United States. At the beginning of September, Nikki Haley, United States ambassador to the United Nations, insinuated that if Trump were to say that Iran deserves to be sanctioned for any one of its various abuses, then this would be enough to torpedo the deal.

In the face of this hypothesis, pinning Iran down again seems practically impossible. The U.S. alone does not have the necessary capability to impose sanctions on Iran severe enough to achieve its objectives, and the European Union, the original architect of JPCOA, has shown itself to be reticent in agreeing to new sanctions if Iran is complying with its commitments. In this scenario, it would be unrealistic to count on the participation of Russia or China.

The repercussions would not be limited to Iran. JPCOA is a rare recent example of international cooperation that demonstrates the viability of a broad range of sanctions, a significant inspiration for an international order based on regulations, which Europe depends on. If the Trump administration buries the deal, it could put future multilateral initiatives in serious danger.

From a regional perspective, the end of the JPCOA will exacerbate the marginalization of the U.S. in the Middle East. The deal with Iran was a key element in former President Barack Obama’s efforts to withdraw from the area, to neutralize one of the greatest sources of instability and constant concern for the U.S. But, far from restoring the status quo ante, destroying the deal would diminish the credibility the United States still holds in the region. In the short term, Russia − which has already seized on the gradual withdrawal of the U.S. from the region to reinforce its presence on the ground − will partially fill the strategic vacuum. After placing itself in a key position with its military involvement in Syria, Russia is now using its energy resources to extend its influence, with serious geopolitical and security consequences.

To date, the state-run company Rosneft has struck deals in Egypt, Iraqi Kurdistan and Libya, and its rival Zarubezhneft has sought to obtain oil and gas development projects in Iran. Meanwhile, Russian gas giant Gazprom is progressing with the construction of the so-called gas pipeline TurkStream. If we also add in the previous NordStream2 project, for a gas pipeline that will connect Russia and Germany, we can see clear evidence of the rapid decline of EU objectives regarding the diversification of its energy sources, an essential element of energy security.

In the long term, U.S. withdrawal from the Middle East will prolong the chaos and destruction that have characterized this decade. The impact will be felt more keenly in Europe, which is becoming increasingly overcrowded. The alternative is that Iran, Saudi Arabia and Turkey reach an unspoken agreement, or indeed a spoken one, on control of the region, excluding foreign forces. In light of the current hostilities in the region, this remains a remote possibility.

This situation also has a clear nuclear element. The JPCOA offered a roadmap to curb the proliferation of nuclear weapons by disconnecting it from its image as a secure and reliable source of energy. If the Trump administration ultimately rejects this model, its future application in new cases will be much more complicated, if not impossible.

European leaders are well aware of the importance of the JPCOA. Now they must act accordingly to save it. To do this, they must establish a constructive relationship with Iran; one that goes beyond fleeting visits that focus on the possibility of European investment and the promotion of an energy alliance, and addresses other unresolved issues, such as ballistic missiles, terrorism and human rights.

The pathway to success in this crisis leads through difficult negotiations, conditionality, and yes, imposing more sanctions. However, we must not contemplate a counter-productive scenario of total embargo. Trump is right when he says that more needs to be done to control Iran, but the JPCOA should be the platform for future actions. That is what it is truly about.