U.S. attack would embolden Iran to pursue nuclear weapon, dooming U.S. to decades long war to contain the threat
An attack could also rally domestic Iranian opinion around weaponization. Currently, there seems to be consensus among Iranians that the country has a right to a robust civilian nuclear program, but there is no domestic agreement yet on the pursuit of nuclear weapons. An attack could tilt the internal debate over the nature of Iran’s nuclear program in favor of those advocating for a nuclear deterrent to prevent future attacks. And, depending on the target set, a strike could also produce significant Iranian casualties, increasing popular support for a regime that is otherwise struggling to maintain its legitimacy. As a result, there is a risk that a strike would doubly backfire by driving Iran to go for the bomb while strengthening the regime.
To prevent Iran from reconstituting its nuclear program after a strike, the United States would have to be prepared to encircle an even more hostile adversary with a costly containment regime – much like the twelve-year effort to bottle up Saddam Hussein after the 1991 Gulf War – and be prepared to re-attack at a moment’s notice. Moreover, in the absence of clear evidence that Iran was dashing for a bomb, a U.S. strike risks shattering international consensus, making post-war containment more difficult to implement. And, with inspectors gone, it would be much harder to detect and prevent Iran’s clandestine rebuilding efforts.
In short, far from being a substitute for containment, a military strike could be the prelude to a decades long containment commitment against an even more implacable nuclear foe.
An attack on Iran's nuclear facilities could have the preverse effect of increasing their timetable for developing nuclear weapons. Assuming that the military strikes do not destroy all of Iran's facilities and their nuclear supplies, Iran will be able to overtly embark on a crash course towards nuclear weapons with more international support.