The Obama administration disclosed the size of the U.S. nuclear arsenal for the first time on Monday, issuing a set of figures that has remained an official government secret since the Manhattan project during World War II.
The administration said the stockpile consists of 5,113 active and inactive warheads, down from a high of 31,255 in 1967, in the years after the Cuban missile crisis.
Although no U.S. administration had ever revealed the current size of its weapons stockpile, the number came as little surprise. Most experts had made estimates close to the actual figures. The Federation of American Scientists, which advocates arms control, for instance, had estimated the inventory at 5,100.
However, administration officials and advocates who supported the public release of the information said the figures would help demonstrate a U.S. commitment to openness about its arms program and prod other countries, especially China, to do likewise.
“We think it is in our national security interests to be as transparent as we can be about the nuclear program of the United States,” Secretary of State Hillary Rodham Clinton said at a news conference at the United Nations. “We think that builds confidence.”
Clinton announced the release of the numbers during an address to the opening session of an international conference to review the Nuclear Nonproliferation Treaty, the cornerstone world treaty on nuclear inventories.
On its first day Monday, the conference flared into an angry public confrontation between the United States and Iran over Tehran’s nuclear program.
Iranian President Mahmoud Ahmadinejad castigated the United States for its use of nuclear weapons in World War II.
Clinton denounced the Iranian president’s “tired, false and sometimes wild accusations,” and called for a crackdown on nations, like Iran, that she said have reneged on their commitments to the nonproliferation treaty.
“Iran will do whatever it can to divert attention away from its own record,” she said.
Clinton pointed to steps the Obama administration is taking to reduce the threat and importance of nuclear weapons, pointing to a new arms reduction agreement with Russia, a revamped U.S. nuclear policy and other measures.
“The United States is showing it is being increasingly transparent in respect to its own nuclear weapons program,” said a senior Defense official, who spoke on condition of anonymity to avoid overshadowing Clinton’s remarks.
The figures released Monday show the number of U.S. warheads in each year from 1962 to 2009, as well as the number of warheads dismantled each year from 1994 to 2009. In 1993, the Department of Energy released historical data on the size of the atomic arsenal for the years before 1962.
The only figure not released is the number of warheads awaiting destruction. Officials said there were several thousand of those weapons, and that they expect to release an exact number in the near future.
The administration also did not disclose how many weapons are active, or nearly ready for use, and those that are inactive, or held in reserve. The figures also do not specify how many are strategic, long-range weapons and how many are shorter-range tactical weapons.
The stockpile will shrink further as the number of strategic warheads is cut to 1,550 if the New START treaty with Russia is ratified.
Hans M. Kristensen, the director of the nuclear information project for the Federation of American Scientists, said the release of the numbers showed it was never really necessary to make them classified information.
In his speech, Iran’s president said U.S. leaders had become “among the most hated … in human history” for their use of nuclear weapons in World War II against Japan. U.S. and European diplomats walked out to show their displeasure.
U.S. officials and their allies are crafting a fourth set of U.N. Security Council economic sanctions in hopes of pressuring Iran to abandon nuclear enrichment. Iran hopes to appeal to non-nuclear developing nations, who resent the nuclear powers’ unwillingness to abandon their own stockpiles.