The foreign policy of the United States of America is bound by the following
- Commitments to NATO, any attack on any NATO country is an attack on all NATO countries.
- Specific bi-lateral commitment to guarantee the Sovereignty and security of the State of Israel.
- Specific bi-lateral commitment to guarantee the security of Taiwan and protection from invasion by Communist China.

Israel does not have the means to threaten a pre-emptive strike against Iran to destroy Iran's nuclear facilities. The Iranians are fully aware of this, they after all built the sites (note plural) in such a way that the IAF could not replicate it's attack against the Iraq facility in the early 1980's.

Ernest is perfectly correct in stating that this at the moment is a dispute between Iran and the UN/IAEA.

By the bye, to those who think that nuclear weapons would not be used against Israel on the reasoning that fall-out would affect neighbouring Arab countries and the Palestinians in the West Bank and Gaza. The Iranians are not Arabs and generally do not give a damn about them, witness to that is the Iranian Government's treatment of it's Arab population in the south-west of the country. As fundamentalist Islamists such a death would guarantee entry into paradise. The only time that atomic weapons have been used was against Hiroshima and Nagasaki in 1945, only sixty-one years ago. What are the current populations of Hiroshima and Nagasaki? And for how long did they cease to be functioning cities after the bombs were dropped? I would reckon that to the likes of Iran's President and the Ruling Council of 12 Old Gits even uninhibitability for 60 years would be a small price to pay for removing, now how did he put it - That disgraceful stain in the Islamic world (i.e. Israel), especially as it would be others that were paying that price.