[JasonC]

Quite. Also, they aren't "nuclear capable" until the nukes involved are small enough to fit. A missile that would fit our most efficient warhead design wouldn't remotely carry an early generation clunker...

[Mr. Quarterpanel]

Two things shoot out in my mind right off:

We don’t know what the payload of the Shahab-3 is, so it is a guess whether the missile can actually carry a nuclear weapon that Iran could produce far enough to reach the target.

Also, just because you have the range, does NOT mean that you can drop it where you want. the fine course control needed in the final stage, just before impact is crucial if you want to hit your target. Otherwise you risk wasting that expensive missile and the nuclear weapon going off (IF it goes off!!) in the desert, missing the target by 100 miles and tipping your hand. It practically begs “NUKE ME!!!!”.

[Rookie Cookie]

You underestimate how easily a primitive Scud type rocket can be mated with a dirty nuclear warhead. Even if low on yield and accuracy it an sure wreak havoc on densely populated areas of Europe and Israel.