"Recent reports suggest that the Bush administration is considering using nuclear weapons against Iran. The very fact that nuclear weapon use is being discussed as an option—against a state that does not have nuclear weapons and does not represent a direct or imminent threat to the United States—illustrates the extent to which the Bush administration has changed U.S. nuclear weapons policy.

"The Bush administration has explicitly rejected the basic precept that the sole purpose of U.S. nuclear weapons should be to deter the use of nuclear weapons. It has assigned a new, and provocative, mission to U.S. nuclear weapons: to dissuade or prevent other countries from undertaking military programs that could threaten U.S. interests in the future. A 'preventive' nuclear attack on Iran would fall into this category. It has also blurred the line between nuclear and conventional weapons by declaring that nuclear weapons can be used as part of military operations.

"This nuclear policy increases the likelihood that nuclear weapons will be used, and ultimately decreases U.S. as well as international security. Instead, the United States should commit itself to strengthen the taboo against the use of nuclear weapons that has developed over the past 60 years.

"Plans to use nuclear weapons against Iran also fail to recognize the immediate dangers inherent in the use of nuclear weapons. The administration is reportedly considering using the B61-11 nuclear 'bunker buster' against an underground facility near Natanz, Iran. The use of such a weapon would create massive clouds of radioactive fallout that could spread far from the site of the attack, including to other nations. Even if used in remote, lightly populated areas, the number of casualties could range up to more than a hundred thousand, depending on the weapon yield and weather conditions.

"Threatening to use nuclear weapons against Iran provides the strongest of incentives for nuclear proliferation, since it would send the message that the only way for a country to deter nuclear attack is to acquire its own nuclear arsenal. The administration cannot have its cake and eat it, too—it cannot have a viable nuclear non-proliferation policy while continually expanding the roles for its own nuclear weapons."