Do you agree that the US should leave Iran alone?
A nuclear Iran may not be a threat to the world as the US government suggests. Iran is politically stable unlike the rest of the middle east, and it's capable of solving it's own problems with the neighbours. Iran has a clean record. However, It is under constant threat of being attacked by Israel as evident from the past.
On the other hand, Israel is safe only because of it's alliance with the US. Should the US depart, Israel would be in danger from all sides of its border. Now the involvement of China in the middle eastern affairs complicates things to a large extent.
I believe either way is going to be tough. Without the US, the middle east would turn into a war zone. Israel would be facing extinction and it may get easier for terrorist organizations to perform their operations. With the US presence, Iran is placed under heavy sanctions and this is affecting the country's economy.