Russians To Sell Iran S-300 SAM System

The Russians have announced the sale of the sophisticated S-300 SAM system to Iran.
While concerning I cannot belive this is a showstopper if U.S. or Israeli forces deem it necessary to take down the Iranian nuclear program.

U.S. Concerned By Russian Sale Of Air Defense Systems To Iran
AGENCE FRANCE-PRESSE, CRAWFORD, TEXAS
The White House expressed concern Dec. 27 over Iran’s announcement that Russia would supply S-300 air missile defense systems to the Islamic republic.
“We have ongoing concerns about the prospective sale of such weapons to Iran and other countries of concern,” Scott Stanzel, a White House spokesman, said from Crawford, Texas, where President George W. Bush was spending the year-end holiday on his ranch.
Iranian Defense Minister Mostafa Mohammad Najjar announced Dec. 27 that Russia would deliver the system but said the date for the delivery would be revealed later. Moscow has not confirmed the sale.
The announcement came as Washington is seeking to impose new U.N. sanctions on Iran over its refusal to halt its nuclear program, which the U.S. fears could be used to build an atomic bomb.
Earlier this year, Moscow frustrated Washington by delivering to Tehran 29 TOR-M1 air defense missile systems, in a deal estimated to be worth $700 million.
Iranian state media touted the S-300 as an even more sophisticated system than the TOR-M1, saying it could hit incoming enemy targets at a greater altitude. Iran said in January it had successfully test fired the TOR-M1.
The U.S. had urged Russia to cancel that sale, saying it was a mistake when the U.N. Security Council had imposed sanctions on Iran’s ballistic missile industry as part of measures against its nuclear drive.