Iran’s New Nuclear Threat

Foreign Policy-June25th2024

By Eric Brewer

In April, the simmering war in the Middle East nearly took a nuclear turn when Tehran launched more than 300 missiles and suicide drones at Israel in retaliation for its strike on the Iranian consulate in Syria. This was Iran’s first direct attack on Israel, and international inspectors stayed away from Iran’s nuclear facilities for fear of a retaliatory response. As the world waited, the Iranian military commander in charge of defending the Islamic Republic’s nuclear sites publicly warned that if Israel attacked the sites, Tehran could revise its nuclear doctrine. This was a thinly veiled threat that Iran might build nuclear weapons in response.

Tehran has long used threats of nuclear expansion to reduce international pressure. But the military commander’s statement highlights a new and dangerous evolution in Iran’s strategy, which is to use the country’s enhanced ability to build a nuclear weapon as a deterrent. Most evidence suggests that Iran is not developing nuclear weapons and Supreme Leader Ali Khamenei has so far put off building them because he sees the risks as outweighing the rewards. But in recent years, Iran has gradually acquired many of the key capabilities necessary to build a nuclear weapon, becoming a so-called threshold state. Iran can now, in a matter of days, produce enough highly enriched uranium to make a bomb. By highlighting its bomb-making potential and responding to specific provocations by threatening to take the final steps to build nuclear weapons, Tehran hopes it can prevent international sanctions and a strike against its nuclear program.

But this strategy is not risk free, and Tehran remains sensitive to the potential security costs of developing nuclear weapons. Stopping Iran from producing a bomb will not be easy, but reducing Tehran’s nuclear capabilities will be even harder. Washington should make Iran a priority and bring U.S. diplomatic and economic might to bear, to prevent the catastrophe of Iran as a permanent threshold state, or one armed with nuclear weapons.

One of the earliest indications that Iran was seeking to use its nuclear threshold capacity as a deterrent appeared in 2023, after France, Germany, and the United Kingdom threatened to reimpose UN Security Council sanctions on Iran if it enriched uranium to weapons grade or transferred missiles to Russia. In response, Tehran threatened to withdraw from the Nuclear Nonproliferation Treaty. That would have removed the most important legal barrier between Iran and the bomb and likely eliminated international monitoring of its nuclear program, meaning that the world would have no way of knowing whether Iran was building a weapon. These threats seem to have had the desired effect. So far, Iran has not enriched to the 90 percent that is typically considered weapons-grade uranium, and Europe has not reimposed sanctions. But with the crisis unresolved, the threats are likely to resurface.