We know that Iran posesses a significant number of weapons that can strike US naval forces. Our navy has wisely decided to position some of its ships in the Indian Ocean, assuming that Iranian reconaissance capabilities are incapable of locating distant US forces. Unfortunately both Russia and China have satellite surveillance systems capable of spotting US carrier groups in the open ocean. The combination of Russian and Chinese targeting data and Iranian missiles could prove deadly to US forces. Were this to occur, it would be the mirror image of America's covert assistance to Saddam during the Iran/Iraq war. Saddam narrowly defeated major Iranian offensives with the aid of American satellite intelligence data.
In an age of precision-guided weapons, anything that can be targeted can be destroyed with a 90% kill probability. This goes for surface ships, as well as for most other weapons systems. If a war between the US and Iran breaks out, the only protection for US forces will be avoidance of targeting. This will not be possible for the land bases in Iraq, which could come under withering missile attack, but bunkers would probably preserve the lives of most personnel, while huge amounts of equipment would be destroyed. For surface ships, attack by precision weapons would be far more damaging. Those that were not sunk outright would be rendered combat ineffective, because even one or two missile hits will neutralize the fragile computer-driven weapons systems of modern warships.
The best protection for our surface ships is evasion of targeting in the vast expanses of the Indian ocean. Although the larger ships have a limited ability to shoot down missiles, this defense can be overwhelmed by a saturation attack, and it may not work at all against the latest generation of supersonic anti-ship missiles. The ability to evade Iranian ocean surveillance of US Naval forces is questionable. Iran has already demonstrated that its rudimentary RPVs (small camera-equipped drones) can locate and shadow a US carrier in the Persian gulf. To locate US ships in the vast waters of the Indian ocean, Iran may turn to Russia and China. These nations have addressed the problem of locating US Carrier groups for many years, and the Russians have powerful radar surveillance satellites that can sweep all the oceans of the world, in both fair and foul weather to detect the position of US carrier groups. It would be reasonable to conclude that the Chinese may have a similar capability.
Note that the sharing of this type of reconnaisance could be easily concealed, but that it would provide Iran with a huge equalizer on the battlefield. For this reason, and many others, we face extraordinary danger in contemplating war against Iran. It is my earnest hope that the US Congress acts to prevent a US military disaster of unprecedented dimensions.