The International Atomic Energy Agency’s Board of Governors passed a resolution on June 20 calling on Iran to cooperate with an agency investigation into possible undeclared nuclear materials and activities.

Given that Iran has stonewalled the IAEA’s investigation over the past year, the resolution’s call for Tehran to “satisfy the Agency’s requests without further delay” is a fair and necessary response to uphold the integrity of the international safeguards regime. Had the Board failed to act on Iran’s case, it could have emboldened other states to stall when the IAEA requests information and access to verify that all nuclear materials are in peaceful purposes.

While the resolution is an important signal of support for nonproliferation norms, it could further escalate tensions over the 2015 nuclear deal known as the Joint Comprehensive Plan of Action — particularly if Iran follows through on its threats to reduce the agency’s access in response and the Trump administration uses the resolution to further justify efforts to collapse the JCPOA.

The IAEA’s investigation is highly unlikely to turn up any smoking gun that would significantly alter the current proliferation risk posed by Iran’s nuclear program. The two reports issued by the IAEA in March and June detailing its concerns make clear that the agency’s focus is on past work, likely from the pre-2003 nuclear weapons program.

The investigation may end up providing more detail about Iran’s past nuclear weapons development efforts, but the JCPOA already took into account the implications of past weaponization work. The U.S. intelligence community concluded in 2007 that Iran had developed the capabilities necessary to build a nuclear weapon, so the limits and monitoring mechanisms negotiated into the JCPOA were designed based on that assessment.

Although the investigation is unlikely to unveil any new threat, Iran’s failure to cooperate with the IAEA undermines Tehran’s credibility and that could have an impact on current perceptions of Iran’s nuclear program. As a member of the Nuclear Nonproliferation Treaty, Iran is legally obligated to implement a safeguards agreement with the IAEA so that the agency can verify the peaceful nature of the country’s nuclear program and that nuclear material is not being diverted for weapons purposes.

As part of the JCPOA, Iran is also implementing a more intrusive voluntary monitoring arrangement known as the additional protocol. The additional protocol provides inspectors more information about a country’s nuclear program and a wider range of tools to verify that the program is peaceful. If Iran refuses to meet its safeguards and additional protocol obligations, it will likely increase speculation, particularly amongst critics of the JCPOA, that Tehran has something to hide.

The resolution also cast a fissure between the remaining P4+1 states party to the JCPOA (China, France, Germany, Russia, and the United Kingdom). France, Germany, and the United Kingdom, also referred to as the E3, drafted the resolution, noting in a June 19 statement that Iran’s decision to deny access for investigators “risks seriously undermining the global safeguards system if no progress is made.”

Russia and China, however, were the only two states on the Board to vote against it. Seemingly referring to the origins of the investigation that prompted the June 20 resolution, China’s Ambassador to the IAEA Wang Qun said that the IAEA acted too hastily in bringing the matter to the Board and asked for more clarification about the legal basis for the agency’s request to access undeclared sites in Iran. Russian Ambassador to the IAEA Mikhail Ulyanov urged Iran and the IAEA to resolve the issues in question, but called the resolution “counterproductive.”

While the E3, Russia, and China continue to support the JCPOA, disagreements over how far to push Iran on the safeguards access question could stymie cooperation on preserving the accord. If Iran continues to stonewall the IAEA and deny access to inspectors, the Board could also choose to escalate by referring Iran’s case to the Security Council.

The Board took this step in 2006 after Iran failed to address the IAEA’s concerns about illicit nuclear activities and the Security Council then passed a serious of resolutions sanctioning Iran. Such action would almost certainly collapse the JCPOA, even if Russia and China veto any new Security Council resolution on Iran’s nuclear activities.

Iran’s response to the resolution could also impact the future of the JCPOA. Most of Iran’s 290-member parliament condemned the resolution as an “excessive demand” and urged the government “to stop voluntary implementation of the additional protocol.” A parliamentary commission later approved the plan.

If Iran follows through on suspending the additional protocol, it could be a death blow to the JCPOA. Over the past year, Iran has carefully calibrated its breaches of the nuclear deal’s limits to push the remaining P4+1 countries to deliver on sanctions relief. By taking modest steps to breach the accord under IAEA monitoring, Tehran has signaled that it is trying to create leverage, not dash for a bomb. Reducing access for inspectors, however, decreases transparency and could push the Europeans to rethink their support for the JCPOA.

Iran’s frustrations with the JCPOA’s failure to deliver sanctions relief envisioned by the deal is understandable. For the last two years the U.S. “maximum pressure” campaign has slowly deprived Iran of almost every benefit of remaining in the accord. But the IAEA’s investigation and the Board’s resolution is not about the JCPOA — it is about ensuring that Iran meets its legal obligations under the NPT and upholding the credibility of the safeguards regime. It behooves Iran to quickly cooperate with the agency and resolve this investigation so it cannot be used further as a bludgeon against the JCPOA.