Iran: The Twelve-Day War, The Day After

With the "Twelve-Day War," President Trump can plausibly claim his first foreign‑policy victory since returning to office. With a relatively limited deployment - five or six bombers carrying heavy bunker-buster bombs (targeting Fordo) and about thirty Tomahawk missiles (on Isfahan and Natanz) - he can allege three simultaneous victories:

• He dealt a significant blow to the Islamic Republic, regardless of (as we will return to) the exact impact on its nuclear program.
• He managed to impose a truce on both belligerents, but most importantly, effectively restrained Israeli Prime Minister Netanyahu, who likely hoped to draw his American ally into a prolonged conflict aimed at regime change in Tehran.
• He resolved the domestic political dilemma posed by the operation: supporters of military action, now rare in U.S. politics, can credit him with a decisive strike; while his base and restraint-minded allies (such as Steve Bannon and Tucker Carlson) may appreciate his quick halt to the campaign.

Beyond these observations, what early lessons can be drawn from this episode? While emphasizing that questions still outweigh certainties, we identify four types of impact from the U.S. intervention: on Iran’s nuclear program, on the Islamic Republic’s regime, on regional and global power balances, and finally… on what comes next.

The Iranian Nuclear Program

Barely had the dust from the bombings settled when a strange quarrel over damage estimates broke out: President Trump claimed Iran's nuclear facilities had been "obliterated", but CNN, echoed by the New York Times, leaked a far more measured analysis from the Defense Intelligence Agency. Rumors spread that Iranian authorities had managed to transfer dozens of kilograms of enriched uranium (notably from Fordo). Satellite images suggest that mostly the outer structures of the nuclear sites were hit. Inside the Iranian regime, the Supreme Leader declared the U.S. strike a total failure, while Foreign Minister Araghchi admitted the nuclear program was damaged. Further American leaks mentioned Iranian officials congratulating one another on how little the strikes had achieved. 

The prevailing consensus seems to be that the program was seriously degraded without truly compromising Iran’s ability to advance toward nuclear weapons - according to IAEA Director-General Rafael Grossi. Trump tacitly acknowledged as much, warning that he is prepared to strike again if necessary. 

Did Israeli strikes decapitate Iran’s nuclear scientific elite? Perhaps, but any effect is unlikely to last, as Mark Goodman and Mark Fitzpatrick note in the Bulletin of Atomic Scientists. However, the Mossad’s astonishing ability to penetrate Iranian systems poses a serious threat to Tehran.

The Iranian Regime

Iran’s leadershipresponded deftly to the U.S. strike, opting for a symbolic counterattack on a U.S. base in Qatar - after warning in advance - thus saving face while avoiding escalation. They quickly claimed victory. At home, the regime unleashed a sweeping crackdown on alleged traitors believed to have facilitated Israeli intelligence breaches. Both reactions were predictable.

Observers initially doubted that the Israeli strikes would trigger a popular uprising capable of toppling the regime. Still, many believed that a prolonged campaign of airstrikes would be fatal for the Islamic Republic. The economic decline and the "Women, Life, Freedom" uprising had already undermined the regime’s legitimacy. The current truce offers a chance for the regime to reassert its authority - by force if not by legitimacy. A hardening of the Iranian state seems likely, akin to Saddam Hussein’s Iraq after the first Gulf War. Iran’s neighbors are concerned, recognizing both the risk of this authoritarian turn and the limited scope of the U.S. operation. In the Financial Times, Émile Hokayem notes a sense of disillusionment among Gulf leaders, who see the region’s stability compromised for years to come.

Will this shift internal regime dynamics? Possibly. Even before the death of Supreme Leader Khamenei, power struggles are likely to emerge, especially within the various security branches (Revolutionary Guards, Intelligence, Army). The centre of gravity could shift further toward these coercive "power structures," at the expense of the clerical hierarchy and civil society.

Regional and Global Power Dynamics

Did the U.S. action reestablish American deterrence or the "strategic centrality" of the United States, to quote Thomas Gomart? There are reasons to doubt it. While Trump has shown a willingness to use force - a signal to Russia, China, and North Korea - his eagerness to end the conflict undermines the deterrent effect. If Trump envisions using force only in very limited ways, are his threats truly credible? A police officer - or better yet, a sheriff - who only fires once, is he really a police officer (or a sheriff)? And would he have drawn his weapon without Israel making the first move?

It followed a recurring pattern: favoring diplomacy (Abraham Accords) and trade, while resorting to limited force when necessary - strikes in Syria in 2017 and 2018 in response to chemical weapons use (contrasting with Obama’s inaction in 2013), the assassination of Quds Force leader Qassem Soleimani in 2020, and threats of sanctions to resolve a dispute with Turkey in 2019 over northeast Syria.

In other words: no American disengagement from the Middle East for the time being, a desire to rely more on regional allies, Israeli and Gulf states (but not Egypt), the ability to use non-kinetic pressure methods, and a willingness to strike militarily, but only in a targeted manner. As mentioned earlier, it is not certain that such an approach will be entirely reassuring for America's Arab allies and leaves room for Chinese and Russian maneuvering.Two major differences between Trump I and Trump II in the region: greater marginalization of Europe (Washington warned no European allies before striking Iran and has no plan to involve them in future talks with Tehran) and the context of the Israeli-Palestinian war. Trump may now attempt to resolve the Gaza situation, even if that means dealing harshly with Netanyahu - again, without involving Europeans.

What Comes Next ?

"The day after" the Twelve-Day War appears to be shaped by two fairly clear conclusions: an even more authoritarian Iranian regime committed to pursuing its nuclear program, and lingering doubt about the U.S.'s willingness to use force beyond short campaigns.

Unless diplomacy takes hold in Washington, Tehran, and Jerusalem - and paradoxically, only Trump might be able to impose such a shift, which would ironically be a true demonstration of American strategic centrality. With or without Europe? The answer will hinge on Europe’s ability to work with Gulf partners-who were unimpressed by the continent’s hesitation during the Twelve-Day War.

Copyright image : Andrew Harnik / GETTY IMAGES NORTH AMERICA / Getty Images via AFP
Defence Secretary Pete Hegseth and Chairman of the Joint Chiefs of Staff Dan Caine at a press conference at the Pentagon on 26 June 2025.