Khamenei long opposed negotiating with Western powers, but he allowed Rouhani to pursue his foreign policy proposal of warmer ties with the West, partly because international sanctions against his regime had ravaged the country’s economy. Khamenei hedged and warned against trusting the United States, while at the same time lending tacit approval to the effort. A growing international consensus against Iran’s nuclear program also emerged and included China and Russia, meaning that Iran would have been totally isolated had it decided to continue advancing toward building nuclear weapons.

Rouhani’s preference for détente inflamed factional disputes inside Iran over the direction of the Islamic Republic. Reformists emphasized a pragmatic approach to the West, while hardline conservatives saw concessions as a sacrifice on the founding principles of the revolution. The factions agreed Khomeini’s ideology should remain the guiding ethos of the Islamic Republic’s policies, as dissenting opinions held by moderates, seculars, and liberals had for decades been systematically repressed. However, they differed over whether and to what extent it should be adapted within a changing geopolitical context. Cautious and ever-suspicious, Khamenei did not take an unambiguous public position on the deal, allowing him to disclaim responsibility for the agreement in the future.

The IRGC pushed back against Rouhani and his supporters’ diplomatic outreach. Not trusting the U.S., this power base reportedly sought Russia’s assistance to sabotage the negotiations, with the former Quds Force commander, Qassem Soleimani, leading the outreach. On a leaked audiotape, Rouhani’s Foreign Minister, Javad Zarif, also often hailed in the West as a moderate regime insider, admitted that the Rouhani Administration’s ability to implement foreign policy was severely constrained, further corroborating how the Supreme Leader’s loyalists in the IRGC dominated the elected state.

Rouhani’s diplomatic initiative was a departure from the Supreme Leader’s vision, which favored self-sufficiency rather than market integration. To reassure his constituency, Khamenei issued harsh rhetoric after the signing of the Iran Nuclear Deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), in July 2015, reaffirming his revolutionary credentials and underscoring how the agreement would not ameliorate fundamental hostility toward the West. Yet, the Obama Administration raised public expectations that the deal would lead to a follow-on deal that would address other areas of Iranian behavior threatening U.S. interests, such as its ballistic missile program, support for terrorism, and human rights abuses. Khamenei foreclosed on that possibility soon after the agreement was signed. In a speech marking the end of the Islamic holy month of Ramadan, Khamenei said, “Whether the deal is approved or disapproved, we will never stop supporting our friends in the region and the people of Palestine, Yemen, Syria, Iraq, Bahrain and Lebanon…Even after this deal, our policy toward the arrogant U.S. will not change. We don’t have any negotiations or deal with the U.S. on different issues in the world or the region.”

The Supreme Leader conditionally approved the deal in October 2015, saying it would be rendered void if additional sanctions were imposed on Iran for human rights abuses or terrorism. In approving the deal, Khamenei dropped his maximalist demands, such as the requirement that all sanctions against Iran be lifted before a deal could be reached. Rouhani sold the nuclear deal to the Iranian people, pointing to how it helped bring the country back from the brink of economic isolation, released more than $100 billion in frozen assets held abroad to the government, and permitted the future deployment of advanced centrifuges that could be used to produce weapons-grade uranium. Then, in early 2016, the Supreme Leader penned an open letter to him in which he suggested it was a good deal, saying, “I express my delight that the resistance of the great nation of Iran against the brutal sanctions, and the endeavors of our nuclear scientists for the progress of the nuclear industry, as well as the indefatigable attempts of the negotiators eventually forced the other side—some of whom are famous for animosity against the Iranian nation—to retreat and lift a part of the bullying sanctions.” This was Khamenei’s fullest endorsement of the deal to date.

Later in the year, however, Khamenei intensified his anti-American rhetoric and walked back his praise for Rouhani’s negotiating team, again reaffirming his revolutionary credentials as he sought to assuage opposition to the deal stemming from his hardline supporters. In his 26th Nowruz speech in Mashhad, he rejected additional negotiations and compromise, saying, “Why was the Qods Force formed? Why were the Islamic Revolutionary Guards formed? Why are the Islamic Republic's policies...based on Islam?...What is the Guardian Council's role in the society? Why is the Guardian Council authorized to reject bills due to their incompatibility with sharia?...This is what I have described several times; this is transformation of the Islamic Republic's essence. The facade of the Islamic Republic might be preserved, but it becomes empty of its content. This is what the enemy wants."

This speech effectively made clear that Khamenei would not make additional concessions in these areas in the future. Neither secular democratic reforms of its legal and political systems nor changes in the modus operandi of the IRGC and its Quds Force were open for negotiation. Still, Khamenei’s conservative supporters accused Rouhani of undermining the Islamic Republic’s sovereignty and impeding Iran’s national security objectives, namely pursuing highly-enriched uranium. While officials opposed to Rouhani voiced these concerns, Iran’s Supreme National Security Council issued a directive to Iran’s Ministry of Culture and Islamic Guidance to order press outlets across the country to put a positive spin on the JCPOA for fear that criticism of the deal would create divisions among political officials. The directive generated more uniform support among the populace while it sought to curtail hardline dissent that might have jeopardized the deal’s implementation.

From the outset, it became clear that Tehran had no intention of moderating its behavior in other areas of concern. In fact, Tehran increased its support for its regional terrorist network of proxies and partners, disbursing large sums of money to them out of the windfall that the unfreezing of assets and sanctions relief had guaranteed. For instance, Lebanese Hezbollah’s coffers were flooded with Iranian largess. The U.S. Department of State reported in 2018 that Hezbollah received $700 million from Iran yearly, allowing it to expand its operations, while other actors in the “axis of resistance” continued to mount attacks against the U.S. and its partners and allies in the region. The IRGC oversaw the proliferation of advanced weapons systems and production capabilities to its proxies and partners. Additionally, Iran accelerated its drone and ballistic missile programs, violating the spirit and intent of U.N. Resolution 2231, which endorsed the JCPOA and “called upon” Iran to limit the range and payload capacity of its missile test launches.

Amid these signs of ongoing Iranian hostility, the election of U.S. President Donald Trump in November 2016 brought a heightened awareness of the deal’s defects and an adamant insistence that Tehran change its behavior or again be squeezed by a U.S.-led sanctions regime. Moreover, U.S. regional partners and allies, such as Israel and Saudi Arabia, remained staunchly opposed to the deal because it provided resources to the Iranian regime’s hostile activities and would provide cover for a nuclear enrichment program down the road.