A nuclear weapon requires more than just uranium and plutonium. They also need to design, build, and assemble a high precision core & all of the metallurgy that takes, the electrical & mechanical components, and explosives to even be able to test a nuclear device.
Then there is the matter of building the weapon system to deliver that nuclear device. The first atom bombs were 10' long, 2-5' wide and weighed nearly 10,000 pounds. Based on the information released to the press Iran had enough nuclear material that was enriched enough to build multiple nuclear devices of the Little Boy weapon type - it's just that their delivery mechanism may have had to be a ship or large cargo plane on a one way mission. Iran's largest current missiles have/had? the capability of launching up to 3,000 lb warhead. Getting down to that size for a nuclear warhead is multiple magnitudes of difficulty greater than what a team that included literally Einstein developed. But it has also been done for 60 years and they have friends with the know how and tools to get it done. Going to intercontinental ranges requires everything that is required for the device to survive reentry and impact relatively near its target. Iran has/had the ability to launch satellites and friends with the other expertise and tools. Lastly, nuclear material decays, so the systems and processes to monitor and replace/recycle the nuclear material need to be developed. That is why if a nation decides to build a nuclear weapon they have to commit to an ongoing program to maintain it. They just cant build them and set them aside in a bunker.
Was Iran developing a nuclear weapons program? I think that answer based on presented evidence is absolutely yes.... if the reports of 400kg of 60% enriched U235 were accurate. Iran's use of cruise and ballistic missiles last summer and in the current conflict are obvious evidence of their weapons development and capabilities. But again, the Iranians didn't start launching them until Israel attacked and the US followed on.
What hasn't been answered or evidenced definitively by the US or Israeli governments is why now... other than Iran hadn't changed their ways, the scales were in our favor, and a unique intelligence opportunity existed.
The downfall of the islamic republic or Iran would be a great thing, but depending on the day it either is or is not what the president wants, though the Israelis have been consistent on wanted change. Meanwhile other adversaries are watching, learning, and waiting. And the day will come when those adversaries assess the scales are in their favor and have a unique intelligence opportunity. We best hope they don't start a war just because the stars seem to align for them.
