The Nuclear Variable: How Iran's Weapons Program Connects to Hormuz Stability
Iran’s nuclear program and the Strait of Hormuz are connected through a logic that diplomatic analysis frequently understates. The connection is not simply that a nuclear-armed Iran would be more willing to close the strait — though that proposition has its own merit. It is that the negotiations over the nuclear program, the sanctions imposed to pressure it, and the diplomatic settlements that have attempted to resolve it are all embedded in the same geopolitical relationship that determines whether the strait operates as a commercial corridor or a conflict zone. The nuclear file and the Hormuz file are the same file.
The Joint Comprehensive Plan of Action, signed in 2015, was premised on a theory that reducing Iran’s nuclear advancement in exchange for sanctions relief would create economic incentives for Iran to remain in compliance, generate domestic political benefits for the moderate faction of the Iranian political system, and — implicitly — reduce the overall temperature of US-Iran relations in ways that would also stabilize the Gulf security environment. The partial validation of this theory: during the period of JCPOA implementation from 2016 to 2018, Iranian naval harassment of commercial shipping in the Gulf declined measurably relative to the years before and after. Whether this reflects a direct connection or coinciding factors is debated. The correlation is real.
The American withdrawal from the JCPOA in 2018 and the reimposition of maximum pressure sanctions produced a predictable sequence. Iranian oil exports fell sharply. Iranian government revenues contracted. The IRGC’s relative institutional weight increased as the economic conditions that moderate Iranian politicians had promised from the nuclear deal failed to materialize. Iranian proxy activity in the region intensified. Tanker harassment resumed. The 2019 tanker attacks were the most acute expression of this sequence, but the underlying logic — that Iran’s behavior in the Gulf is connected to the economic and diplomatic conditions it faces — was visible throughout.
The subsequent negotiations to restore or replace the JCPOA have repeatedly foundered on the same fundamental problem: neither side trusts the other’s commitments sufficiently to make the concessions that would allow a deal to close. Iran does not trust that an American agreement would survive the next administration’s review. The United States does not trust that Iran’s nuclear activities would remain constrained if sanctions were lifted and Iranian revenues recovered. Both of these concerns are empirically grounded in recent history. The impasse is rational.
The alternative to a diplomatic resolution of the nuclear file — a military strike on Iranian nuclear facilities — has been analyzed exhaustively. The consensus that emerges from this analysis, across multiple governments and think tanks, is that a military strike would set back Iranian nuclear development by some years while simultaneously triggering a military response that would include, with high probability, Iranian action in the strait. A strike that successfully degraded Iran’s nuclear program by eighteen months would purchase that eighteen months at the price of a Hormuz closure that could last for weeks or longer, depending on the scope of the Iranian response and the military campaign required to suppress it. The tradeoff is not obviously favorable.
Iran’s nuclear threshold status — its ability to produce weapons-grade material relatively quickly if a political decision to do so were made — is itself a form of leverage over the Hormuz calculus. A nuclear Iran, or a threshold Iran, cannot be pressured through threats of military action in the way that a conventional Iran can. The deterrent that the nuclear program provides against regime change scenarios also provides cover for more aggressive behavior in the strait. The connection runs from weapons program to military posture to commercial shipping in a direct line.
The strait’s stability and the nuclear file’s trajectory are linked. Any analysis of Hormuz that treats the nuclear question as a separate issue is analyzing half a problem.