The Islamic Regime in Iran is the biggest problem in the Middle East. They were behind a lot of terrorism including Isis & encouraged & supplied their weapons.They've also proclaimed many times that they want to wipe Israel off the map.
The West suspect they are trying to produce nuclear weapons and all this is the outcome.
Israel cant allow Iran to go nuclear.
In the 70s before the Islamists took over, Iran (Persia) was westernised and friends with the West.