Military force may have delayed Iran’s nuclear ambitions – but history shows that diplomacy is the more effective nonproliferation strategy

While the U.S. military’s strikes on Iran on June 21, 2025, are believed to have damaged the country’s critical nuclear infrastructure, no evidence has yet emerged showing the program to have been completely destroyed. In fact, an early U.S. Defense Intelligence Agency assessment^[1] surmised that the attack merely delayed Iran’s possible path to a nuclear weapon by less than six months. Further, Rafael Mariano Grossi, director of the United Nations’ International Atomic Energy Agency, stated that Iran may have moved its supply of enriched uranium^[2] ahead of the strikes, and assessed that Tehran could resume uranium enrichment “in a matter of months.”

Others have warned that the strikes may intensify the Islamic Republic’s nuclear drive^[3], convincing the government of the need to acquire a bomb in order to safeguard its survival.

As a scholar of nuclear nonproliferation^[4], my research indicates that military strikes, such as the U.S. one against Iran, tend not to work. Diplomacy — involving broad and resolute international efforts — offers a more strategically effective way to preempt a country from obtaining a nuclear arsenal.

The diplomatic alternative to nonproliferation

The strategy of a country using airstrikes to attempt to eliminate a rival nation’s nuclear program has precedent, including Israel’s 1981 airstrike on Iraq’s Osirak nuclear reactor^[5] and its 2007 air assault on Syria’s Kibar nuclear complex^[6].

Yet neither military operation reliably or completely terminated the targeted program. Many experts of nuclear strategy believe that while the Israeli strike destroyed the Osirak complex, it likely accelerated^[7] Iraq’s fledgling nuclear program, increasing Saddam Hussein’s commitment to pursue a nuclear weapon.

In a similar vein, while Israeli airstrikes destroyed Syria’s nascent nuclear facility, evidence soon emerged^[9] that the country, under its former leader, Bashar Assad, may have continued its nuclear activities elsewhere.

Based on my appraisal of similar cases, the record shows that diplomacy has been a more consistently reliable strategy than military force for getting a targeted country to denuclearize.

The tactics involved in nuclear diplomacy include bilateral and multilateral engagement efforts and economic tools ranging from comprehensive sanctions to transformative aid and trade incentives. Travel and cultural sanctions – including bans on participating in international sporting and other events – can also contribute to the effectiveness of denuclearization diplomacy.

The high point of denuclearization diplomacy came in 1970, when the majority of the world signed the Treaty on the Non-Proliferation of Nuclear Weapons^[10]. The treaty obliged nonnuclear weapons states to refrain from pursuing them, and existing nuclear powers to share civilian nuclear power technology and work toward eventual nuclear weapons disarmament.

I’ve found that in a majority of cases since then – notably in Argentina, Brazil, Libya, South Africa, South Korea and Taiwan – diplomacy played a pivotal role in convincing nuclear-seeking nations to entirely and permanently relinquish their pursuit of nuclear weapons.

Case studies of nuclear diplomacy

In the cases of U.S. allies Argentina, Brazil, South Korea and Taiwan, the military option was off the table for Washington, which instead successfully used diplomatic pressure to compel these countries to discontinue their nuclear programs. This involved the imposition of significant economic and technological sanctions on Argentina and Brazil in the late-1970s, which substantially contributed to the denuclearization of South America^[11]. In the South Korea and Taiwan cases, the threat of economic sanctions was effectively coupled with the risk of losing U.S. military aid and security guarantees^[12].

South Africa represents one of the most compelling cases in support of diplomatic measures to reverse a country’s nuclear path. In the latter years of the Cold War, the country had advanced beyond threshold nuclear potential to assemble a sizable arsenal of nuclear weapons^[13]. But in 1991, the country decided to relinquish that arsenal, due in large part to the high economic, technological and cultural costs of sanctions^[14] and the belief that its nuclear program would prevent its reintegration into the international community^[15] following years of apartheid.

Completing the denuclearization of Africa, diplomatic pressure applied by the U.S. was the primary factor in Libya’s decision to shutter its nuclear program in 2003^[16], as ending U.S. sanctions and normalizing relations with Washington became a high priority^[17] for the government of Moammar Gadhafi.

In the case of Iraq, the Hussein regime eventually did denuclearize in the 1990s, but not through a deal negotiated directly with the U.S. or the international community. Rather, Hussein’s decision was motivated by the damaging economic and technological costs of the U.N. sanctions and his desire to see them lifted^[18] after the first Gulf War.

In the 11 countries in which diplomacy was used to reverse nuclear proliferation, only in the cases of India and Pakistan did it fail to induce any nuclear reversal.

In the case of North Korea, while Pyongyang did for a time join the Treaty on the Non-Proliferation of Nuclear Weapons, it later left the accord and subsequently built an arsenal now estimated at several dozen nuclear weapons^[19]. The decades-long efforts at diplomacy with the country cannot, therefore, be coded a success. Still, these efforts did result in notable moves in 1994 and 2007 by North Korea to curtail its nuclear facilities^[20].

Meanwhile, analysts debate whether diplomacy would have been more successful at containing North Korea’s nuclear program if the George W. Bush administration had not shifted toward a more confrontational policy, including naming North Korea as a member of the “axis of evil”^[21] and delaying aid promised in the 1994 U.S.-North Korean Agreed Framework^[22].

The Iran deal and beyond

Consistent with the historical track record for diplomacy concerning other nuclear powers, Iran offers compelling evidence of what diplomacy can achieve in lieu of military force.

Diplomatic negotiations between the U.S, Iran and five leading powers yielded the landmark Joint Comprehensive Plan of Action^[23] in 2015. The so-called Iran deal involved multilateral diplomacy and a set of economic sanctions and incentives, and persuaded Iran to place stringent limits on its nuclear program for at least 10 years and ship tons of enriched uranium out of the country. A report from the International Atomic Energy Agency in 2016 confirmed that Iran had abided by the terms of the agreement^[24]. Consequently, the U.S., European Union and U.N. responded by lifting sanctions.

It was only after President Donald Trump ordered the U.S. withdrawal from the agreement in 2018, and reimposed sanctions on Iran, that Tehran resumed its alarming enrichment^[26] activities.

Trump signaled quickly after the recent attack on Iran a willingness to engage in direct talks with Tehran. However, Iran may rebuff any agreement that effectively contains its nuclear program, opting instead for the intensified underground approach Iraq took after the 1981 Osirak attack.

Indeed, my research shows that combining military threats with diplomacy reduces the prospects of successfully reaching a disarmament agreement. Nations will be more reluctant to disarm when their negotiating counterpart adopts a threatening and combative posture^[27], as it heightens their fear that disarmament will make it more vulnerable to future aggression from the opposing country.

A return to an Iran nuclear deal?

Successful denuclearization diplomacy with Iran will not be a panacea for Middle East stability; the U.S. will continue to harbor concerns about Iran’s military-related actions and relationships in the region.

It is, after all, unlikely that any U.S. administration could strike a deal with Tehran on nuclear policy that would simultaneously settle all outstanding issues and resolve decades of mutual acrimony^[28].

But by signing and abiding to the terms of the JCPOA, Iran has demonstrated a willingness to cooperate on the nuclear issue in the past. Under the agreement, Iran accepted a highly limited and low-proliferation-risk nuclear program subject to intrusive inspections by the international community.

That arrangement was beneficial for regional stability and for buttressing the global norm against nuclear proliferation. A return to a JCPOA-type agreement would reinforce a diplomatic approach to relations with Iran and create an opening for progress with the country on other areas of concern.

References

1. ^{^} U.S. Defense Intelligence Agency assessment (www.nytimes.com)
2. ^{^} may have moved its supply of enriched uranium (www.npr.org)
3. ^{^} intensify the Islamic Republic’s nuclear drive (www.realcleardefense.com)
4. ^{^} scholar of nuclear nonproliferation (scholar.google.com)
5. ^{^} Israel’s 1981 airstrike on Iraq’s Osirak nuclear reactor (theconversation.com)
6. ^{^} 2007 air assault on Syria’s Kibar nuclear complex (www.theguardian.com)
7. ^{^} likely accelerated (theconversation.com)
8. ^{^} Jacques Pavlovsky/Sygma via Getty Images (www.gettyimages.com)
9. ^{^} evidence soon emerged (www.spiegel.de)
10. ^{^} Treaty on the Non-Proliferation of Nuclear Weapons (disarmament.unoda.org)
11. ^{^} which substantially contributed to the denuclearization of South America (www.wilsoncenter.org)
12. ^{^} the risk of losing U.S. military aid and security guarantees (www.nonproliferation.org)
13. ^{^} sizable arsenal of nuclear weapons (isis-online.org)
14. ^{^} high economic, technological and cultural costs of sanctions (isis-online.org)
15. ^{^} prevent its reintegration into the international community (education.cfr.org)
16. ^{^} shutter its nuclear program in 2003 (www.belfercenter.org)
17. ^{^} ending U.S. sanctions and normalizing relations with Washington became a high priority (www.brookings.edu)
18. ^{^} costs of the U.N. sanctions and his desire to see them lifted (web.archive.org)
19. ^{^} several dozen nuclear weapons (www.congress.gov)
20. ^{^} result in notable moves in 1994 and 2007 by North Korea to curtail its nuclear facilities (www.congress.gov)
21. ^{^} naming North Korea as a member of the “axis of evil” (www.armscontrol.org)
22. ^{^} delaying aid promised in the 1994 U.S.-North Korean Agreed Framework (globalasia.org)
23. ^{^} Joint Comprehensive Plan of Action (www.cfr.org)
24. ^{^} Iran had abided by the terms of the agreement (www.crisisgroup.org)
25. ^{^} AP Photo/Ronald Zak (newsroom.ap.org)
26. ^{^} U.S. withdrawal from the agreement in 2018, and reimposed sanctions on Iran, that Tehran resumed its alarming enrichment (www.npr.org)
27. ^{^} when their negotiating counterpart adopts a threatening and combative posture (assets.cambridge.org)
28. ^{^} decades of mutual acrimony (theconversation.com)