By killing the anti-nuclear leadership of such country and proving their opponents points that only nukes could protect them from the USA...
It was called JCPOA but Israel didn't like it because it would've meant peace for the region. War _is_ the point for Israel at this point.
Further, the agreement allowed Iran to develop more advanced centrifuges. The kind which could be used to enrich uranium to weapons grade.
Further, the agreement left substantial nuclear infrastructure and expertise intact. For example, Fordow was not dismantled and 1,044 IR-1 centrifuges remained there. Natanz also retained thousands of operating centrifuges.
In 2025, the IAEA concluded that Iran had failed to declare nuclear material and nuclear-related activities at Lavisan-Shian, Varamin, and Turquzabad, and could not determine the whereabouts of some nuclear material.
The JCPOA allowed Iran to significantly expand its military capabilities and strengthen the regime via economic sanction relief, the release of hundreds of billions of dollars of Iranian international assets, and normalisation of trade (most notably oil). Iran used this opportunity to consolidate power without any material commitment or action towards sustainable cessation of nuclear weapons research and capability.
One could argue that it was the best of all bad options on the table, but let us not pretend it was a good option. Iran has been funding death and terrorism all over the world for decades. Its stated goal is the annihilation of many Western nations. The treatment of its own people is beyond comprehension and description. It routinely practises the rape of virgin women before execution (for things like not dressing modestly, or protesting), so that these young women will end up in hell. If the world were just, the entire world would unite to invade Iran, remove the dictator class from power, and implement democracy.
Just to be crystal clear: none of what I have written states nor implies that Trump has handled this conflict well.
Sorry, but all you did was:
1. Showed them and the world that treaties with you are worth nothing
2. Showed them and the world, to gain the respect of the US, you need nukes. Decades of loyalty, treaties or good partner have been shown to be worth nothing, while being an authoritarian dictatorship and having nukes are respected.
3. Showed them and the world that having US bases on your soil is a liability and not a protection.
All in all if you were US president and your task was to destroy the US' standing in the world, there is not much more you could have done.
Trying to keep yourself dry with a newspaper over your head in a hurricane: pointless.