Never underestimate the enemy. The Iranian regime is an enemy of the United States and Israel. It is not rational in the sense western style democracies are rational. Iran has announced the intention to destroy both Israel and the United States. If they develop the capability to accomplish their stated goals, we must assume they will use it. Capability is what counts, not crystal ball assumptions regarding intentions. If the current Iranian regime has nukes, sooner or later they will use them.