Believe it or not, Tehran and Washington are already negotiating. Not in the shadows of a stuffy European hotel, but via a rhetorical exchange happening in plain sight.

Despite President Joe Biden’s condemnation of his predecessor’s Iran policy and the president’s stated desire to return to the 2015 nuclear accord that Donald Trump left, his cabinet appointees say that America is in no rush. Iranian officials have responded with great variety. On the one hand, they claim that Tehran no longer needs the Joint Comprehensive Plan of Action (JCPOA), the nuclear agreement’s official moniker. On the other, they call on Washington to rejoin the deal immediately because the “window of opportunity will not be open forever.” They are also adamant that the accord’s parameters cannot change and that America must take the first step through the lifting of sanctions.

Should the United States re-enter the JCPOA, it will matter comparatively little if it does so in six days or six months. That is because the major limitations on the Islamic Republic’s nuclear and missile programs are expiring, meaning Washington would be rejoining an accord that is a ghost of its already toothless self. Such a move would be a disservice to America’s nonproliferation objectives, as well as to President Biden’s nascent Iran policy.

A closer look at the text of the JCPOA and its accompanying United Nations Security Council (UNSC) resolution (2231) explains why.

Lapsing Limitations

At the heart of the JCPOA is a “Faustian bargain” between temporary constraints on Iran’s atomic program and long-term Western sanctions relief. The JCPOA essentially required Iran to ship out uranium and put select nuclear equipment in storage so as to lock-in, for about a decade, the technical conditions needed for a seven-to-twelve month “breakout time”—the amount of time needed to make enough fissile material for a nuclear weapon. That the JCPOA did not actually resolve the Iranian nuclear dispute is seen in Tehran’s ability to quickly ramp-up its uranium enrichment capacity over the past few months and in revelations that it likely maintains a secret weaponization program.

Moreover, the agreement’s original members—the United States, UK, France, Germany, Russia, and China—agreed to a series of lapsing limitations on Iran, most of which occur after five, eight, ten, and fifteen years, colloquially termed “sunsets.” The sunsets, codified in various annexes of the 150-plus page document and in Annex B of the accord’s associated UNSC resolution, gradually permit Iran to ramp up its nuclear program and let other missile and military restrictions expire.

In 2024, or eight and half years from the deal’s commencement, the JCPOA’s restrictions relating to Iran’s advanced centrifuge research and development will start to lapse. This will permit Tehran to gradually begin testing, manufacturing, and conducting research on select sturdier machines that can spin uranium at greater speeds. The ultimate goal of this phased approach, for Tehran, is to capitalize on sunsets related to enrichment that lapse between years ten to fifteen of the deal. Advanced centrifuges are essential to any prospective Iranian dash to a nuclear weapon, since they produce enriched uranium more quickly using fewer numbers. Under the JCPOA, Iran can continue researching and advancing these improved centrifuges, and likely kept buying equipment to position the program for mass deployment at a time of its choosing.

Should Biden re-enter the Iran deal, the JCPOA will loosen centrifuge restrictions so that Iran’s breakout time will drop to mere weeks in the coming years. This means that foreign countries would not—absent the use of military force—be able to stop a determined Islamic Republic during a potential breakout scenario.

Similarly timed missile and military sunsets can be found in Annex B of UNSC resolution 2231.

The UN resolution’s next sunset occurs in October 2023, terminating an UN-sponsored asset freeze on persons and entities supportive of Iran’s nuclear program, as well as ending an already watered-down injunction against Tehran’s ballistic missile launches. Iran uses missile tests to signal resolve to domestic and foreign audiences while collecting data from launches to make its projectiles more battlefield ready, survivable, and reliable. While 2231’s prohibitions against missile activity are more narrowly scoped than older resolutions, Tehran has consistently violated its injunctions. From the JCPOA’s finalization in 2015 until U.S. withdrawal in May 2018, Iran launched at least twenty-five ballistic missiles. If Iran sought to genuinely reduce tensions with the international community during this period, that number would have been zero.

In year eight, the resolution also removes the UN prohibition on Iranian imports and exports of missile-related equipment and materiel, as defined by the Missile Technology Control Regime (MTCR). This means Tehran could procure and proliferate controlled, sensitive equipment like accelerometers, flight-control systems, sensors, motor casings, turbojet or turbofan engines, and propellant production equipment more easily. These materials can improve both Iran’s ballistic missile arsenal—which according to U.S. intelligence is largest in the Middle East—as well as the long-range strike capabilities of its proxies and partners like Lebanese Hezbollah or the Houthi rebels in Yemen.

Impending Enforcement Challenges

But there is no reason to look so far ahead. In fact, the resolution’s first major sunset already occurred in October 2020. In addition to eliminating a global visa ban against Iranian officials and others working on proliferation-sensitive programs (which was regularly violated), the UN arms embargo against Iran expired. Established in 2007 through UNSC resolution 1747, and tightened under UNSC resolution 1929 in 2010, the embargo on Tehran’s ability to import and export military equipment was tied to its long-standing regional interventions and not subject to lifting by a political timetable. UNSC resolution 2231 changed that, terminating the embargo after only five years, regardless of Iran’s behavior.

To date, Iran has violated both the embargo’s import restrictions, through attempted illicit missile procurement, as well as the export prohibitions via weapons proliferation to militias in Iraq and to the Houthis in Yemen. The embargo’s presence, however, along with countries’ ability to interdict transfers, made life harder for Iran. Now with it gone, Tehran can more easily arm its proxies and pursue a policy of selective military modernization, the consequence of which will be a more lethal and aggressive Islamic Republic. Coupled with a robust terror network, resolute and ideological leadership, and a “patient pathway” to a nuclear bomb, an unencumbered Iran will pose a potent hybrid warfare challenge to U.S. interests and allied security in the region.

Even though the Trump administration used its legal status as a “JCPOA participant” at the UN to argue that it had reinstituted the arms embargo, none of the other UNSC members recognized the U.S. right to do. Washington followed up with an executive order (13949) threatening sanctions on those who would enable Iranian military-related procurement or proliferation. It is unclear how long the Biden administration will retain or enforce this unilateral prohibition.

All the lapsing restrictions on Iran’s nuclear program, ballistic missile testing, and arms-transfers amount to major strategic concessions. Yet Tehran’s real win was locking up U.S. and European oil and financial sanctions, which originally helped bring about negotiations in 2013. The JCPOA obliges Washington to legislatively nix all sanctions statutes related to Iran’s nuclear program by October 2023.

October 2023 is also when, pursuant to the JCPOA’s implementation timeline, the United States is required to purge select persons and entities tied to Iran’s nuclear program from its sanctions lists. This includes the likes of Mohsen Fakhrizadeh, Iran’s now-deceased chief military nuclear scientist, as well as SPND, the entity he oversaw that researches nuclear weaponization. The icing on the cake for Tehran is that Washington’s chief partner in economic pressure, the European Union, will also be removing a plethora of proliferation and terrorism-supporting entities from its sanctions lists by October 2023. The European list contains a veritable “who’s who” of malign actors that even includes Iran’s now-deceased terrorist chief, Qassem Soleimani.

The European list also includes Iran’s Ministry of Defense and Armed Forces Logistics (MODAFL), sanctioned on proliferation grounds by the EU, and under both counterterrorism and counter-proliferation authorities by the U.S. Treasury. MODAFL subordinates and contractors constituting Iran’s military-industrial complex, like Iran Electronics Institute (IEI), Defense Industries Organization (DIO), Aerospace Industries Organization (AIO), as well as AIO’s subordinates like Shahid Hemmat Industries Group (SHIG) and Shahid Bagheri Industries Group (SBIG) are also on the list for EU sanctions removal in 2023. AIO, SHIG, and SBIG all support Iran’s evolving missile capabilities, be they through the development of liquid or solid propellant platforms.

Not only will Europe be un-handcuffing the literal engines of Iran’s missile arsenal in October 2023, they will also de-list portions of the Iranian military establishment that oversee Iran’s missile program. These include the Islamic Revolutionary Guard Corps (IRGC), the IRGC Aerospace Force (IRGC-AF), the IRGC-AF Al-Ghadir missile command, and even IRGC-AF Commander Amir-Ali Hajizadeh. The EU’s prospective delisting of Iran’s military brain trust will make it virtually impossible for Washington to build a united trans-Atlantic pressure policy toward Tehran that seriously addresses the Iranian missile challenge.