The United States has made public the number of nuclear warheads in its arsenal.  Recently declassified information reveals that the United States had 5,113 warheads in its nuclear weapons stockpile as of last September.

Daryl Kimball, Executive Director of the Arms Control Association, a private research firm, breaks down the numbers.

"That includes the number of strategic [long-range] deployed warheads as well as warheads held in reserve - strategic warheads held in reserve as well as tactical [short-range or battlefield] warheads," said Kimball.  "It does not include the warheads that are retired and awaiting dismantlement, which independent experts believe to be in the four to 5,000 range."

That figure and other statistics were released by the Defense Department. But the announcement was made by Secretary of State Hillary Clinton at the opening session of the Nuclear Nonproliferation Treaty review conference in New York earlier this month.

Secretary Clinton told reporters revealing the number does not weaken U.S. national security.

"We think it is in our national security interest to be as transparent as we can about the nuclear program of the United States. We think that builds confidence," she said.

Experts - such as Daryl Kimball - say for decades, the exact number of nuclear warheads in the U.S. arsenal was a tightly held secret.

"For a long time, the view was that if the United States and other countries reveal the number of nuclear warheads that they have, they may, number one - reveal certain weaknesses to the main opponent, in the United States' case, the Soviet Union," Kimball added.  "Second, it may help reveal the amount of plutonium and highly-enriched uranium it takes to build a nuclear device. That latter fact has been known for quite some time."

Many analysts have welcomed the Obama administration's decision. One of those is retired Ambassador Tom Graham, a senior diplomat who has been involved with the negotiation of every arms control and nonproliferation treaty of the past 30 years.

"This is a decision that should have been taken years ago. I see no reason why post-Cold War, especially many years post-Cold War, why this kind of information cannot be publicly available," said Graham.  "And I would encourage the other nuclear weapon states - all of them - to do the same thing. It adds to public confidence, it adds to international stability. So I regard this as a very positive step."

But former U.S. ambassador to the United Nations and arms control expert John Bolton takes the opposing view.  He says giving out the number of nuclear warheads in Washington's arsenal is a mistake.

"There is utility in not having that number confirmed in public - it leaves potential adversaries guessing," noted Bolton.  "And it's an unforced error - it is a concession that the Obama administration made in the hope that it would bring the United States goodwill internationally.  It is evidence of the administration's extraordinarily naïve view that somehow it's the U.S. nuclear capability that is provocative around the world and that if we display transparency, other governments will give up their proliferation aspirations and be just overwhelmed with our goodwill and that peace and sweetness will break out."

Analysts, such as Ambassador Tom Graham, say the U.S. announcement comes at a time when nuclear-related issues are making headlines.

"The [U.S.] nuclear posture review has just been released, the New START Treaty was recently signed, we just had the nuclear security summit," Graham added.  "More has happened in the nuclear security and the nuclear nonproliferation field in the last two months than in the past 10 years."

Graham and others say the focus now is on the month-long NPT review conference in New York. Analysts say the gathering of more than 180 countries must find ways to strengthen the treaty and thus keep the spotlight on nuclear weapons issues.