Iran’s interest in acquiring an advanced nuclear capability dates back to early 1970s, when the Shah of Iran, thanks to the massive influx of oil revenue, embarked on an ambitious path to expand Iran’s then limited nuclear industry. Prior to that, Iran ratified the Treaty on the Non-Proliferation of Nuclear Weapons in 1968. Tehran’s early nuclear program was very limited and posed no proliferation risk. Meanwhile, the political storm that swept Iran in 1979 forced the country’s nuclear program into a complete hibernation. With the country’s former nuclear chief Ahmad Sotoodenia imprisoned and many nuclear scientists seeking better opportunities in the west, the revolutionary regime cancelled foreign contracts and abandoned many ongoing projects. However, as the initial fervor subsided, Tehran began to slowly pick up the pieces of the Shah’s ambitious nuclear program and essentially followed the nuclear policies of the Pahlavi regime, despite their strong resentment toward the last Persian monarch. The following historical analysis examines the strategic logic behind Iran’s decision to reconstitute the Shah’s nuclear program. By examining the historical milestones of Iran’s nuclear program, this study will help analysts better understand the future of Iran’s nuclear ambitions. A number of factors influenced the clerical regime’s decision to halt Iran’s nuclear program. the new leaders believed that nuclear technology was too expensive, and that it made Iran technologically dependent on the West. Fereydoun Sahabi, a trained geologist and the first chief of Atomic Energy Organization of Iran (AEOI) under the Islamic Republic, complained in May 1979 that “…Apart from technical difficulties, we are facing soaring costs which were never predicted when these agreements were first signed.” Second, ideological factors played a critical role in Tehran’s decision making. For the revolutionary leaders, the nuclear program was a complicated and “western” technology that made Iran dependent on foreign assistance, contradicting one of the pillars of revolution, Esteghlal or independence. In this context, Abbas Taaj, then Iran’s Minister of Energy, claimed that “..because the implementation of the contract [with KWU] would have made Iran dependent on outside sources from the standpoint of technology…and since the contract embodied colonialist features…it was rejected by the Iranian Government.” Finally, and perhaps most importantly, Ayatollah Khomeini’s religious-based opposition to nuclear weapons was a major factor in Iran’s nuclear hiatus. His July 1979 assertion that the unfinished plants in Bushehr would be used as “wheat silos” sealed the fate of Iran’s nuclear industry- at least for the time being. The outbreak of Iran-Iraq war (1980-1988) fundamentally changed Tehran’s nuclear calculus, forcing some military commanders and pragmatic politicians to rethink the country’s nuclear dormancy. Shortly after the outbreak of the conflict in September, the Iranian air force attacked the Osirak nuclear power plant. The attack failed to inflict significant damage. While the Israeli air force destroyed the Osirak nuclear reactor in June 1981, scholarly works indicate that Iraq continued working on “dirty bombs” until 1987. Interestingly, the clerical regime used the Shah’s justifications for “peaceful” uses of nuclear energy and diversification of Iran’s energy resources to reconstitute nuclear program. Nevertheless, the timing suggests that the military exigencies trumped other motivations. As Ayatollah Hashemi explained in an interview in 2015, “When we first began, we were at war and we sought to have that possibility for the day that the enemy might use a nuclear weapon. That was the thinking. But it never became real…” The horrifying use of chemical weapons during the Iran-Iraq war (1980-1988), which reportedly began as early as 1981, played a foundational role in Iran’s decision to seek a nuclear deterrent. During this period, the international community largely ignored Iraq’s violations despite Iran’s complaints to draw international attention to these atrocities. These events strengthened the view that Iran cannot rely on international norms to prevent the use of WMDs, thus encouraging Iran to seek nuclear weapons as a deterrent. In this regard, Ayatollah Hashemi Rafsanjani is famously quoted as saying “…the moral teachings of the world are not very effective when war reaches a serious stage…and the world closes its eyes to the aggressions committed on the battlefield. We should fully equip ourselves both in the offensive and defensive use of chemical, biological and atomic weapons.” Indeed, Iran’s nuclear behavior during this period is a case in point of security models of nuclear proliferation wherein states facing existential threats seek the protection of a nuclear deterrent. Evidence suggests that Iran resumed its interest in the nuclear field as early as May 1981, when AEOI sponsored a seminar to review economic and technical feasibilities of construction of nuclear power plants in Iran. Iranians also began small scale uranium conversion activities at Isfahan Nuclear Technology Center (INTC), which was completed with Chinese assistance in 1984. Additionally, Iran reached out to India in 1982 (albeit rebuffed) seeking assistance in completing the Bushehr nuclear power plant. During this period, western intelligence sources began speculating about Iran’s nuclear intentions. A September 1985 U.S. National Intelligence Council assessment projected that while Iran remained interested in developing a nuclear deterrent, it would not be able to so before the end of war with Iraq. However, in 1987, Iranians successfully acquired the technical schematics of P-1 centrifuges from Pakistan’s A.Q. Khan network, which set the foundation for the first generation of Iran’s IR-1 centrifuge machines. The Iran-Iraq war left an indelible mark on Iran’s national and political psyche. Iran’s economy and infrastructure were in shatters and close to 200,000 Iranians had lost their lives in the conflict. Meanwhile, Iraq and its large arsenal of conventional and chemical weapons continued to pose a threat to Iran. These security threats led Iranians to actively expand their nuclear program. This expansion was possible due to president Hashemi Rafsanjani’s (1989-1997) unequivocal support for the program, and the death of Ayatollah Khomeini, (1989) who opposed nuclear weapons. In this context, the decade following the end of the war witnessed a full-fledged expansion of Iran’s nuclear program. In 1991, Iran secretly imported 1.6 tons of uranium products from China, without declaring it to the IAEA. Iran and Russia further signed an agreement in January 1995 in which Russia pledged to complete the Bushehr nuclear power plant. To compensate for the loss of manpower of the post-revolution years, Iran also began training its own nuclear cadre. For example, the Iranian government gave a $3 million loan to Italy’s Trieste nuclear center and sent 77 nuclear scientists for advanced nuclear training. During the same period, Iranians also continued their work on mastering the nuclear fuel cycle. By the year 1999, Iranians successfully enriched Uranium in a cascade of 19 IR-1 centrifuges at the Kalaye-Electric Company near Tehran. Several consequential and interrelated events significantly impacted Iran’s nuclear program, pushing Tehran to fundamentally shift its nuclear policies in 2003 and halt its quest for a nuclear deterrent. For one, the terrorist attacks of 9/11 and the subsequent U.S. invasion of Iraq removed the primary threat to Iran. Furthermore, revelations of Iran’s secret underground enrichment facility at Natanz in August 2002 put the spotlight on Iran’s covert nuclear activities. Adding to the pressure during this period was President Bush’s “freedom agenda,” and the “preemptive war” doctrine, in addition to overt threats of regime change. These factors arguably convinced Tehran that it should avoid giving any excuse to the Bush administration to invade the country. In this context, one could make the case that Iranians had assessed that the country’s nuclear program is not only incapable of deterring a US invasion, but could in fact be used as the pretext for the U.S. invasion of Iran. Tehran’s attempts to reach out to Washington and Iranian offers of cooperation support this assessment. This is in line with the 2007 National Intelligence Estimate (NIE) estimate and the archive of Iran’s nuclear program stolen by Israel, which both suggest that Iran abandoned its quest for a nuclear deterrent in 2003. The debate on the direction of Iran’s nuclear program is a multifaceted puzzle which will continue to draw attention for the foreseeable future. Will Iran cross the threshold and weaponize its decades long nuclear program? Based on the evidence provided in this analysis, the short answer is ‘no.’ Given its staggering financial costs, in addition to political and diplomatic ramifications, Iran is very unlikely to weaponize its nuclear program unless its geostrategic environment deteriorates drastically. This can explain why Iran’s current Foreign Minister has previously observed that nuclear weapons will in fact run counter to Iran’s interests. However, any potential proliferation of nuclear weapons in the region or existential threats could strongly induce Iran to seek to acquire the ultimate defensive weapon. Recently, Iran’s Minister of Intelligence, Mahmoud Alavi, told Iran’s State TV that “Our nuclear program is peaceful and the fatwa by the supreme leader has forbidden nuclear weapons, but if they push Iran in that direction, then it wouldn’t be Iran’s fault, but those who pushed it.” In short, Iran’s approach to its nuclear question is primarily driven by its strategic environment and security threats, and ideological issues play a miniscule if any role in Iran’s nuclear program. Sina Azodi is a nonresident fellow at the Atlantic Council and a visiting scholar at the George Washington University’s Institute for Middle East Studies. He is also a PhD Candidate in International Relations at University of South Florida. Follow him on Twitter @Azodiac83.