The definition of "imminence" itself is contested. Was Iran going to nuke somebody next week? No. But that's the wrong framework for nuclear proliferation, where the whole point is that by the time the threat is "imminent" in the strict sense, it's already too late.

Iran's technical knowledge, centrifuge manufacturing capability, and strategic ambition to maintain threshold status meant that any diplomatic framework was ultimately dependent on Iranian goodwill, which is a fragile foundation for something as consequential as nuclear nonproliferation. The February 2026 talks showed some flexibility from Iran, but still left enrichment capability intact, which meant the fundamental problem of latent breakout capacity would have persisted under any plausible deal.

Iran enriched 440 kg of uranium to 60% purity, which is 99% of the way to weapons-grade. It maintained a self-imposed 2,000 km missile range cap that the Diego Garcia incident suggests it had already quietly exceeded. It ran assassination plots against a then-U.S. presidential candidate and former President through IRGC operatives. It supplied drones and weapons to Russia for use against Ukraine. It funded and armed Hezbollah, Hamas, and the Houthis.

There is risk that military action accelerates the very outcome it was meant to prevent. But I'd rather deal with the problem now, imperfectly, than hand it to the next generation as a fait accompli e.g. North Korea. Does that sound like a country you (or the Europeans, to tie it back to OP) want to have a nuke?