Just a minute...
It's not clear to me that Iran intends to attack anyone; this is a paranoid totalitarian regime that fears attack, and has clearly learned the lesson of North Korea: if the rest of the world thinks you're crazy and you have the bomb, they'll all leave you alone. QED, if your motive is regime survival then you go for the nuclear option as fast as you can.
Seen with Iranian eyes and paranoid outlook, they will see Israel and some American politicians publicly calling for Iran to be attacked, Condi Rice in town to call them terrible people and agree to sell USD20bn of weapons to the sunni Arab states and give USD30bn over the next ten years to Israel, already the regional superpower.
All of which may mean that if your goal is regime survival, you'll want to have the best defence you can get, and you'll go to the suppliers who will supply you - in this case, the Russians.
S41