Only if Harris wins.
US needs Iran to keep its own allies in check?
There is no difference between Trump and Bush on Iran policy. No breach of the NPT will be tolerated as the consequences will spread. Which means the sanctions will come back again.
Once the fracking started Obama didn't see the gulf arabs as important to the regions stabilty as had been American policy since FDR. So moved to improve relations with Iran. The trouble is the deal struck left open the option to go nuclear in the future rather than foreclosing it.
A regime change in Iran will help stability in the region. But the US no longer has the stomach for it.
An open question is whether the Israelis lose their relevance to the gulf Arabs once Iran is no longer a threat. The answer to that is no if oil ceases to be as important in the future as it was in the past. The gulf arabs have to diversify their economies away from oil to secure their future and Israel will be a key partner in doing so
Yes, it has and these two are going to be at it but can't do a lot because of the distance.
I would have said China. They will lose the discounted Iranian oil if Trump comes back. We moved off Iranian oil when Trump sanctioned iran and haven't returned since.