US military action in Iran risks igniting a regional and global nuclear cascade.

The Conversation, Farah N. Jan, Senior Lecturer in International Relations, University of Pennsylvania, January 30, 2026

The United States is seemingly moving toward a potential strike on Iran.

On Jan. 28, 2026, President Donald Trump sharply intensified his threats to the Islamic Republic, suggesting that if Tehran did not agree to a set of demands, he could mount an attack “with speed and violence.” To underline the threat, the Pentagon moved aircraft carrier USS Abraham Lincoln – along with destroyers, bombers and fighter jets – to positions within striking distance of the country.

Foremost among the various demands the U.S. administration has put before Iran’s leader is a permanent end to the country’s uranium enrichment program. It has also called for limits to the development of ballistic missiles and a cutting off of Tehran’s support for proxy groups in the Middle East, including Hamas, Hezbollah and the Houthis.

Trump apparently sees in this moment an opportunity to squeeze an Iran weakened by a poor economy and massive protests that swept through the country in early January.

But as a scholar of Middle Eastern security politics and proliferation, I have concerns. Any U.S. military action now could have widespread unintended consequences later. And that includes the potential for accelerated global nuclear proliferation – regardless of whether the Iranian government is able to survive its current moment of crisis.

Iran’s threshold lesson

The fall of the Islamic Republic is far from certain, even if the U.S. uses military force. Iran is not a fragile state susceptible to quick collapse. With a population of 93 million and substantial state capacity, it has a layered coercive apparatus and security institutions built to survive crises. The Islamic Revolutionary Guard Corps, the regime’s military wing, is commonly estimated in the low-to-high hundreds of thousands, and it commands or can mobilize auxiliary forces.

After 47 years of rule, the Islamic Republic’s institutions are deeply embedded in Iranian society. Moreover, any change in leadership would not likely produce a clean slate. ……………………………………………….

What strikes teach

Whether or not regime change might follow, any U.S. military action carries profound implications for global proliferation.

Iran’s status as a threshold state has been a choice of strategic restraint. But when, in June 2025, Israel and the U.S struck Iran’s nuclear facilities, that attack – and the latest Trump threats – sent a clear message that threshold status provides no reliable security.

The message to other nations with nuclear aspirations is stark and builds on a number of hard nonproliferation lessons over the past three decades. Libya abandoned its nuclear program in 2003 in exchange for normalized relations with the West. Yet just eight years later, NATO airstrikes in support of Libyan rebels led to the capture and killing of longtime strongman Moammar Gaddafi……………………………………………………………………………………………………………………………………………………………………………

The domino effect

Every nation weighing its nuclear options is watching to see how this latest standoff between the U.S. and Iran plays out.

Iran’s regional rival, Saudi Arabia, has made no secret of its own nuclear ambitions, with Crown Prince Mohammed bin Salman publicly declaring that the kingdom would pursue nuclear weapons if Iran did.

Yet a U.S. strike on Iran would not reassure Washington’s Gulf allies. Rather, it could unsettle them. The June 2025 U.S. strikes on Iran were conducted to protect Israel, not Saudi Arabia or Iran. Gulf leaders may conclude that American military action flows to preferred partners, not necessarily to them. And if U.S. protection is selective rather than universal, a rational response could be to hedge independently………………………………………………………………………………………………………………………………………………………..

And the nuclear cascade would not likely stop at the Middle East. ………………………………………… https://theconversation.com/us-military-action-in-iran-risks-igniting-a-regional-and-global-nuclear-cascade-274599