Answer: We'd take Iran back to the middle ages.
Question: What would happen if a small band of terrorists hit New York or Israel and killed millions of citizens??
Answer: Obama would be picking cards with names of terrorists on them for assassination.That's why any State involvement would stay hidden.
I have every confidence many in the US know quite well what happened with this craft and are biding their time (if it's still intact and usable), or are checking over the debris field as we speak, if not.
HF
I think that plane could disappear from Iran, and Iran could plausibly deny involvement - just about as well as they could with anything that they were actually involved in doing.
The government / intel agencies would know the truth. The news media would act to suppress the truth because it is BOTH sides best interests.
(AS WAS DONE WITH TWA 800 - The CIA zoom climb video on TV and spontaneous center fuel tank explosion was the truth?)