You could have just elevated Onias IV, and avoided all this mess.
"Proportionate" response is Jimmy Carter language. The Iranian regime will never give up its nukes, no matter what they say or sign. We must be honest with ourselves. Time will prove me right, and others who understand this. It's now or likely never.
If we cannot remove the uranium, then seriously consider contaminating the sites so no one can go anywhere near them for 100 years or more. Remember the 1966 Palomares accident (you can look it up).
Any further delays in taking out this regime, and that includes arming the people, will result in both unforeseeable and predictable consequences that will be severe and constant for us, our allies, and the West generally. If not immediate then over time. No amount of negative PR campaigns against Israel or Netanyahu, who best understand the nature of things in that region, will change that. No amount of lobbying by Arab states and Turkey, who have their own interests and priorities (sound familiar) that may not and, in some cases, clearly do not align with ours, should sidetrack us.
Yes, we may lose the midterm elections, for a host of reasons that have not changed even before the war with Iran. It would be disastrous in many ways, given the radicalism of the Democrat Party and its intent to destroy our constitution, border, and economic system. But if we are perceived as losing this war, or as failing to finish the job, or declare victory without victory, it will be used against us. Victory just happens to also be good politics. The longer it takes, the more difficult it becomes.