... and do it in the middle of the night, local time, when the solar flux is at minimum. That will give maximum unimpeded path for Compton electrons.
May be they could have that ability in the future - but it isn't today. They have to prove they can make one, make it small enough for them to fit on a rocket and make it dependable. Some how avoid detection, set up a missile base to accomodate this long range rocket and launch it. OBTW, this is without Israel getting in the first punch and taking out or significantly delaying Iran's program. There are a slew of "what if's" and "maybe's" that have to be accomlished first.