Since the mid 1980s the Western bloc has been highly concerned with the possibility of Iran developing a nuclear weapon, a concern which has grown with time and led the United States and a number of European states to take extensive measures against the Islamic Republic. These measures have included threats of war, preparations for potential preventative strikes on Iranian nuclear facilities, economic sanctions, and application of immense pressure and the United Nations to push for an international response in line with Western interests. With Pakistan and North Korea having both withstood immense Western pressure to develop nuclear capabilities in the 1990s and the 2000s respectively, and North Korea doing so despite by far the harshest UN sanctions in world history being applied to it, Iran was long expected to become the world’s 10th nuclear power in the 2010s.
The drafting of the JCPOA nuclear deal under the U.S. Obama Administration, which saw little means of further restricting Iranian nuclear development other than direct military intervention, was a means for the United States and its Western allies to forestall Iran’s emergence as a nuclear power. With the administration having announced America’s ‘pivot to Asia,’ under which the U.S. would concentrate its efforts and refocus its military towards the Asia-Pacific from the Middle East, a region arguably far more critical to U.S. interests, involving the U.S. military in a major and likely protracted war in the Persian Gulf appeared highly undesirable. Withdrawal from the JCPOA by the Trump administration, in light of an apparent refocusing towards the Middle East and a need to maintain the security of Israel, a small U.S. aligned nuclear power which faces a growing Iranian sponsored military presence on its borders, has however brought the potential for conflict over the nuclear issue to the forefront once again.
While the threat of Iranian nuclear development, which would according to a number of Western analysts allow Tehran to establish it as a dominant military power in the Middle East as well as undermine the Israeli nuclear advantage, is an often covered subject, the origins of the Iranian nuclear program are not. Before the 1979 Iranian revolution, which saw the Western aligned Pahlavi dynasty ousted from power, Iran had in fact been supplied with much of what it needed to develop a nuclear weapon by the United States - with full knowledge of what the nuclear materials could be used for. Assistance escalated in 1974, and a CIA proliferation assessment that year stated that there was "no doubt" that Tehran would use this assistance to develop a nuclear arsenal by the mid 1980s. The Shah himself stated that Iran would become a nuclear power "without a doubt and sooner than one would think." The United States was knowingly supporting the proliferation of nuclear weapons to the Middle Eastern state, but as the development was set to strengthen the Western bloc’s position rather than undermine it it was perceived as an asset rather than being portrayed as an existential threat to International security. With Israel at the time having already developed a nuclear weapon, the Western bloc was to have two nuclear armed clients in the Middle East - a monopoly which would leave Soviet aligned regional powers at a severe disadvantage.
Nuclear assistance to Iran was carried out under the Atoms for Peace initiative, under which the United States provided a number of valuable strategic partners with facilities to produce nuclear energy - an attempt to win over these nations in light of the growing competition for influence with the Soviet Union. With Iran bordering the USSR, its overwhelmingly pro Western leadership including the European educated Shah provided the United States with valuable military facilities on the Soviet border, while the military was a leading client for Western arms which were pointed squarely at the Soviet Union. A nuclear armed Iran would cause further security concerns for the USSR, far moreso than a nuclear armed North Korea has for the United States today considering the distance between them, and much of the infrastructure the United States provided Tehran could be used to produce plutonium and weapons grade highly enriched uranium, the two critical materials needed to make nuclear bombs. Israel was also reportedly supportive of the Iranian nuclear program, which would provide its primary regional ally with capabilities to better combat their common enemies in the region.