On Nov. 27, Mohsen Fakhrizadeh was assassinated on a road outside of Tehran. An Iranian nuclear scientist who reportedly led the Islamic Republic of Iran’s alleged covert nuclear weapons program in the early 2000s, Fakhrizadeh most recently served as a brigadier general in Iran’s Ministry of Defense and Armed Forces Logistics, as head of the ministry’s Defensive Research and Innovation Organization (DRIO). He also taught physics at Imam Hossein University, an institution associated with the Islamic Revolutionary Guards Corp.

Iran’s leadership has blamed Israel for the attack, but Israel has neither confirmed nor denied any involvement. Some analysts voiced concern that the killing was meant to provoke an Iranian retaliation — a move that might then trigger U.S. military strikes on Iranian nuclear sites. If this is what the perpetrators hoped they may be disappointed, as Iran has signaled strategic patience as it waits for the incoming Biden administration to take office. Those plotting the assassination may also have viewed Fakhrizadeh as indispensable to Iranian clandestine defense projects, given his managerial experience and proximity to the highest echelons of power in Iran.

And there’s a further possible explanation: The assassination could make the road back to the Joint Comprehensive Plan of Action (JCPOA) nuclear agreement and follow-up agreements harder for the incoming Biden administration. Potential follow-up agreements include extending and strengthening the JCPOA’s nuclear provisions, as well as restricting the Iranian ballistic missile program and efforts to curb the activities of Iran’s proxy networks in the Middle East. Thus, while none of these three motivations are mutually exclusive, this may be the most enduring legacy of the Fakhrizadeh killing, part of the larger U.S. and allied “maximum pressure” campaign.

How will this affect Iran’s nuclear program?

It’s not clear how Fakhrizadeh’s death might impact Iran’s nuclear program. Fakhrizadeh is believed to have been involved in the nuclear talks in some capacity and received one of Iran’s highest honors for his service. However, his active role, if any, in Iran’s nuclear program before his death is otherwise unclear.

The effects of his death on the DRIO, tasked with overseeing advanced defense R&D, is also difficult to discern without knowing the details of his work or the organization’s pool of personnel to draw on. Leadership changes in any organization entail disruption. But the nature of R&D projects, institutionalization of knowledge in Iran’s military-industrial complex and the DRIO’s relatively deep human resources pool suggest Fakhrizadeh’s death may have a limited impact.

Could it mean war?

While the perpetrators of this attack may have hoped to draw the Iranian government into a military conflict with the United States during the Trump administration’s remaining weeks in office, there’s little evidence to suggest Iran’s calculus has changed. There have been calls for vengeance from across Iran’s leadership and political spectrum. But under its policy of “strategic patience,” Iran has absorbed successive blows from the U.S. “maximum pressure” campaign since May 2018. These include one of the most punishing sanctions regimes in recent memory, an aggressive cyber offensive and sabotage effort against Iran’s critical infrastructure including nuclear facilities, and the assassination of senior government personnel.

Iran is likely to retain a degree of deniability if the government decides to take any immediate military response — and any such move would also be calibrated to avoid triggering a larger conflagration with the United States. This would be in keeping with how Iran has countered U.S. maximum pressure tactics in the past. However, Iranian officials have promised retribution in a time, place and manner of their own choosing, so any unattributed response in the near future might not be the end of the story.

What about the Iran nuclear deal?

A number of pundits have argued that Fakhrizadeh’s killing could strengthen the hand of Iranian “hard-liners,” complicating Iran’s approach to the JCPOA and any future negotiations with the United States, Europe and other participants in the agreement. The ripple effects could be more complicated. Iran’s conservatives and moderates in key power centers probably share at least two objectives between now and the country’s June 2021 presidential election: avoiding a military conflict with the United States and alleviating sanctions pressure. Many factors might preclude these goals, but Fakhrizadeh’s assassination is not necessarily one of them.

The Iranian parliament last week passed a law requiring the Rouhani government to end cooperation with the International Atomic Energy Agency (IAEA) by February 2021 if the Biden administration does not lift key sanctions by then. This is ostensibly a response to the late-November attack, but also falls squarely within Iran’s approach of ratcheting up pressure on the JCPOA participants since May 2019.

An IAEA report leaked last week also noted that Iran plans to install advanced centrifuges at a new underground location in the Natanz nuclear facility, another breach of the nuclear deal if implemented. These moves probably signal to the Biden administration that Iran can generate its own pressure — and that any such moves are reversible if the United States returns to compliance with its nuclear deal obligations.

Fakhrizadeh’s killing raises a further hurdle to any efforts to strengthen and prolong the JCPOA’s nuclear provisions, as such steps would involve IAEA monitoring and verification. Access to individuals is part of painting a complete and accurate picture of a country’s nuclear program. But conservatives have blamed the IAEA for revealing the identities of Iranian nuclear scientists and thus making them targets. Iran has also recently threatened legal action against the IAEA over the leak of a confidential report to the media. Deeper distrust of the IAEA could hamper cooperation and rationalize shrouding the program in further secrecy to protect its personnel. The violent death of Fakhrizadeh also raises the thorny issue of what steps participants in the JCPOA might be willing to take to protect the agreement from sabotage by outside parties.

Whatever damage or delay those behind the Fakhrizadeh killing hoped to achieve, we are unlikely to see a larger U.S.-Iran military conflict as a result, or significant setbacks for Iran’s nuclear capacity. These actions could, however, weaken the nonproliferation regime by sowing distrust that makes it harder to reach, monitor and verify nuclear deals with Iran in the future.

Farzan Sabet is a researcher in the Middle East Weapons of Mass Destruction Free Zone (ME WMDFZ) Project at the United Nations Institute for Disarmament Research.