Of course, a nuclear weapons capability comes with the territory: Any nation with a fully developed nuclear fuel cycle has such a weapons capability. In fact, this could be considered a major flaw in the Nuclear Non-proliferation Treaty. For instance, Japan, Argentina, and Brazil also have a latent nuclear weapons capability. Just like you can't get a speeding ticket for a car that is capable of going 110 miles per hour, it is not illicit to have a latent nuclear weapons capability.
An Israeli strike on Iran could change this latent capability into an active weaponization program. Iran’s response would likely include the expulsion of IAEA inspectors and a break-neck race to the bomb – not to mention the possibility of a region-wide conflagration and sky-high gas prices.
An Israeli strike would also have a “rally-around-the-flag” effect on the Iranian populace, allowing the regime to crack down further on political opponents and silence critics, cementing the regime’s authority.
Recent analysis shows that a previous Israeli strike – in 1981, on Iraq’s civilian Osirak nuclear reactor complex – led Saddam Hussein to demand a nuclear deterrent and was actually the trigger for Iraq launching a full-scale effort to weaponize. A decade later, by the time of the 1991 Gulf War, Iraq was on the verge of a nuclear weapons capability.
As researcher Malfrid Braut-Hegghammer explains in a recent International Security article, such ostensibly “preventive attacks can increase the long-term proliferation risk posed by the targeted state.”