Iran’s decision to begin enriching uranium up to 60% and the recent attack on the Natanz nuclear facility were reminders of the difficulties that world powers will encounter in reviving and building upon the nuclear deal (JCPOA). As the United States, the P4+1, and Iran gather in Vienna in a bid to resurrect the JCPOA, three inconvenient truths abound: the political contexts in the United States and Iran have changed since 2015; there are inherent tensions in the Biden administration’s approach to Iran; and there are onerous technical talks ahead related to sanctions and Iran’s nuclear escalation.

A complicated domestic political calculus

The domestic landscapes in Tehran and Washington have shifted since the original nuclear deal was inked. On the U.S. side, President Biden is a first term commander-in-chief grappling with a pandemic; nursing a wounded economy; and dealing with a slate of other more pressing challenges. In contrast, in 2015, President Barack Obama was in his second term, and the presidential inbox was not as overwhelming as it is today. While it is true that Republicans controlled two houses of Congress in 2015, President Biden still faces narrow margins in the U.S. Senate—a 50-50 split between Republicans and Democrats—as well as fewer Democratic seats in the U.S. House of Representatives. This dynamic, coupled with competing priorities, may limit the amount of political capital President Biden will choose to spend on resuscitating an original agreement that was controversial and highly unpopular among almost all Republicans and some influential Democrats, including the current U.S. Senate Majority Leader Chuck Schumer and the Chairman of the U.S. Senate Foreign Relations Committee Bob Menendez. In sum, racing to re-join an agreement, without demanding any changes, like lengthening sunset provisions or at the very least extracting some binding commitment for follow-on negotiations, could be a bridge too far for President Biden.

The situation in Iran is complicated as well. The presidential election is scheduled to take place on June 18, and the electoral jockeying has already started. While it is the supreme leader, Ayatollah Ali Khamenei, who has the final word on the nuclear file and the president lacks independent decision-making authority in this context, the presidency does have input as chairman of the Supreme National Security Council (SNSC). But the incumbent President Hassan Rouhani faces competition from two ambitious and more conservative officials—Speaker of Parliament Mohammad Bagher Ghalibaf and Chief Justice Ebrahim Raisi—who have been mentioned as potential presidential candidates and hold seats on the SNSC as well. They are unlikely to defer to Rouhani. Raisi offered veiled criticism of Rouhani allies last week, saying “if they had dedicated the time spent on seeking the West’s concessions to boosting domestic production, the problems would have been solved.”

With the octogenarian supreme leader ageing, the Islamic Republic’s next president could very well be his last. As a result, the political space for pragmatists like Rouhani may shrink if Ayatollah Khamenei aims to pave the way for a more hardline disciple in this post, which may make Tehran more uncompromising during the Vienna talks to avoid giving Rouhani’s allies a boost during the election. In his speech on March 21, Khamenei complained that Iranian officials rushed into the JCPOA in 2015, but that now he is in no such hurry. Likewise, while Rouhani had initially dangled a step-by-step approach for achieving compliance-for-compliance with the nuclear deal, Khamenei has instead adopted a more aggressive posture in demanding that the United States lift all sanctions in one step. The Iranian public position has also toughened into not just demanding the removal of all sanctions issued under the Trump administration, but also to the recreation of the sanctions landscape dating back to the JCPOA’s adoption in 2015—when President Barack Obama was in office. Although on Thursday, Iran’s deputy foreign minister indicated some flexibility, saying “[t]here is room to negotiate how to identify sanctions.” Thus, while Khamenei has greenlighted these Vienna talks and thrown a bone to Rouhani, his team may be on a short leash.

Duelling campaign promises

In the commentary in Washington, it is often emphasized that President Biden made a commitment to re-enter the JCPOA during the 2020 campaign. But he made another commitment, and that was to use the accord as a platform to ink a longer and stronger agreement with the Islamic Republic that addresses the shortcomings of the original deal. The challenge for the Biden administration is that the 2015 nuclear deal and its broader architecture have already started to expire—for instance, the arms embargo under U.N. Security Council Resolution 2231, which endorsed the JCPOA, lapsed in October 2020. An overwhelming majority of the U.S. House of Representatives in May 2020 called on the then Trump administration to make efforts to renew the embargo, even though its expiration was negotiated by the original JCPOA drafters. The limitations on Iran’s ballistic missile program under the same Resolution 2231 are scheduled to expire by October 2023. The snapback mechanism is slated to lapse two years later in 2025. That is not to mention the nuclear sunsets in the JCPOA itself, for which the clock has already started ticking.

To date, despite campaign slogans about the virtues of the nuclear deal, the Biden administration has never publicly detailed how it plans to ensure Tehran has any incentive to negotiate a more exacting deal if it merely re-enters the first one with no amendments. Indeed, Iranian officials have stated publicly they are against such negotiations. But it is the conclusion of an improved accord that is important to opening the door to even the possibility of bipartisan support for the Biden diplomacy, not to mention reassuring U.S. allies and partners in the Middle East. Thus, it is this second Biden promise that is crucial for Washington that he deliver on but controversial in Tehran.

Defining compliance

Lastly, and most significantly, defining compliance will prove to be a significant undertaking. The JCPOA was premised on the easing of nuclear-related sanctions. But there were also a multitude of missiles-, terrorism-, and human rights-related designations which have been added to the U.S. sanctions arsenal during the Trump presidency. In recent days, Iran’s deputy foreign minister has defined U.S. compliance as “all of the U.S. sanctions that were re-imposed after Trump’s withdrawal (from the JCPOA), or have been imposed recently, or have been re-labeled, must be defined and the U.S. must remove them.” As mentioned above, this position has evolved into a demand for the restoration of 2015 conditions. Thus, Tehran is stating very clearly it will demand certain non-nuclear U.S. sanctions be revoked as a part of the revival of the agreement. Likely candidates include the terrorism sanctions levied on the Central Bank of Iran, the Ministry of Petroleum, and the National Iranian Oil Company under Executive Order 13224. If the Biden administration were to agree to take such a step, it would run into a political buzzsaw on Capitol Hill, given the evidence the U.S. Treasury Department has presented in justifying such designations.

Likewise, an Iranian domestic debate has emerged in recent days over the concept of verification—meaning how Tehran would verify that the U.S. sanctions have indeed been lifted. Rouhani himself has stated that verification “will not take much time” and his foreign minister tweeted it can be done in a rapid manner. But Iran’s Parliament Research Center in a new report warned that this process cannot be concluded in mere hours or days. Instead, it is estimating it will take three to six months. Such a timeline would likely be a nonstarter for the United States without Iranian steps to scale back its nuclear escalation.

And these sanctions minefields do not even begin to address how to tackle the technical knowledge Tehran has gained since U.S. withdrawal from the JCPOA. In the end, resurrecting a years-old nuclear accord is much harder than it looks.