How Many Nuclear Warheads?

June 1, 2008

Eighteen months from now, the Strategic Arms Reduction Treaty (START I) will expire, raising questions about what takes its place. Six months from now, a Congressional commission will report its ideas about the future shape of US strategic forces. Today, the Pentagon is gearing up for a far-reaching nuclear posture review.

For the first time in years, strategic nuclear arms issues are moving up on the governmental priority list. Among the more important questions to answer is this one: How many nuclear warheads does the US really need

Beginning with START I, the US agreed, in a succession of treaties and negotiations, to drastically lower its warhead inventory. START II and START III never entered into force. Bars indicate highest allowable numbers.

Today, Washington maintains a force of just under 3,000 operational warheads. They are deployed aboard intercontinental ballistic missiles, submarine-based ballistic missiles, and B-2 and B-52 heavy bombers.

Two decades ago, the story was very different.

In 1988, with the Cold War still in high gear, the US had an enormous inventory of some 13,000 strategic nuclear warheads. The Soviet Union, for its part, had even more.

Soon, however, the forces began to shrink. President Ronald Reagan and Soviet leader Mikhail Gorbachev agreed, in principle, to make deep reductions in their strategic arsenals, paving the way for START I, signed in 1991.

START I mandated that each superpower would draw down, by 2001, to 6,000 “accountable” warheads, on 1,600 delivery vehicles.

Next came START II (which was ratified but never went into force). It would have further cut inventories to 3,000 to 3,500 warheads and banned multiple warheads aboard ICBMs. The last of the START series, START III, was never completed; drafts called for limiting each nation to 2,000 to 2,500 warheads.

START II and START III fell by the wayside because Washington and Moscow lost interest in them. They were superseded in 2002 by the more ambitious Strategic Offensive Reductions Treaty (SORT), also known as “The Moscow Treaty.” Under SORT, the two nations agreed to cut their operationally deployed strategic warheads to a level between 1,700 and 2,200 by the end of 2012.

The START/SORT drawdown has been gradual but steady. At the end of 2007, the US was down to 2,871 “operationally deployed” warheads.

(One sometimes hears that the US has 6,000 warheads. This is the “START-accountable” number, which is losing relevance because weapons are counted in a contrived and obsolete way.)

So, the US must still shed close to 700 warheads. Washington has made no public announcements about how it plans to do so, but the State Department said in 2005 it “anticipated,” among other things, “lowering the number of … warheads at heavy bomber bases.”

Everyone assumes the US will meet SORT’s goal. The real question is: Should reductions go even deeper? Gen. Kevin P. Chilton, the Air Force officer who serves as head of US Strategic Command, reports that he is “comfortable” with the numbers allowed under the Moscow Treaty, but not fewer.

Even though the US has dispensed with nearly 75 percent of its Cold War inventory, the answer for many is that the reductions should be continued. Prominent arms control advocates maintain that the US could get by just fine with as few as 1,000 or even 500 nuclear weapons—enough for a “minimum deterrent” force.

Some would go to zero. This is the case with four prominent strategic affairs experts—former Secretaries of State George P. Shultz and Henry A. Kissinger; former Secretary of Defense William J. Perry; and former Chairman of the Senate Armed Services Committee Sam Nunn. They call for “further substantial reductions in US and Russian nuclear forces” beyond those dictated by SORT, with the final goal being “a nuclear-free world.”

At the other end of the spectrum, some hawks in Congress, the Pentagon, and the services think today’s inventory already is too small or, at a minimum, should not be further reduced.

Those who favor maintaining the SORT level argue that a large arsenal is needed to meet the requirements of deterrence under the current US Nuclear Weapons Employment Policy, signed out in 2004. To quote the document: “US nuclear forces must be capable of, and be seen to be capable of” destroying an enemy’s military forces, ability to wage war, and the other things a potential enemy’s leadership values most.

Quite a few experts say that would require more than a handful of nukes.

As for going to zero, that seems out of the question for now. Maj. Gen. Roger W. Burg, commander of 20th Air Force (overseer of the nation’s ICBM fleet) said nuclear abolition is an “attractive and seducing” thought that, nonetheless, ignores reality.

Russia, China, North Korea, India, and Pakistan are all nuclear armed and embroiled in long-standing disagreements with either the United States or one or more of its friends and allies.

So what is the right number for the United States

Plans call for the Pentagon to complete its next nuclear posture review in December 2009. It will seek to balance the benefit of a strong nuclear deterrent against the desire to limit the danger of nuclear war. Only then—in the political arena but with the Air Force’s input—will we know the answer.