In April 2009, President Barack Obama outlined his vision for a world free of nuclear weapons before thousands of enthusiastic people in Prague’s Hradcany Square. Development of the nation’s new nuclear doctrine, documented in the Nuclear Posture Review (NPR), was subject to intense speculation in the popular press and, when the document was finally released — for the first time unclassified in its entirety — it became, if only briefly, a hot topic of political debate.

In April 2009, President Barack Obama outlined his vision for a world free of nuclear weapons before thousands of enthusiastic people in Prague’s Hradcany Square. Development of the nation’s new nuclear doctrine, documented in the Nuclear Posture Review (NPR), was subject to intense speculation in the popular press and, when the document was finally released — for the first time unclassified in its entirety — it became, if only briefly, a hot topic of political debate.

The next step of the process — actually implementing the new policies and doctrine — is where the rubber hits the strategic road. The very high-level, but necessarily general, even vague, policy direction of the NPR has to be translated into specifics: What nuclear weapons do we need, what should their characteristics be, and what targets should the weapons be aimed at? This process is, arguably, even more important than setting forth a vision, however grand; but it is virtually invisible and is getting almost no notice outside the tiny group in the government responsible for developing the plans.

The re-examination of nuclear missions comes at a critical juncture because the nation’s nuclear delivery systems — its bombers, submarines, and missiles — need replacement, starting in a decade or so.

The nuclear weapons that the United States designs today could be in its arsenal a half century from now, sharply constraining how the country can manage its nuclear forces. Once the weapons are built, the Navy can’t operate half a submarine, and the Air Force can’t change the flight time of a missile. At the very least, decisions about new nuclear weapons ought to explicitly look at facilitating their eventual elimination. When Pentagon planners sketch out the next nuclear missile, they should be thinking about how it can easily be moved to lower levels of alert some time in the future, how it will survive and be stable at low numbers, and how partners in arms control can verify all this.

While little information is available on the Pentagon’s thinking, what has come out unfortunately suggests unimaginative, straightforward extrapolation of where the country is today. For example, proposals for a new nuclear missile submarine include essentially reproducing today’s submarine, perhaps a bit smaller and a bit slower. We can do better.

It is futile to seek further reductions in the numbers of nuclear weapons, or even their alert status, without first reducing some of the nuclear weapons missions — that is, the types of military tasks the weapons are expected to perform. The first mission that should be abandoned is the most challenging and dangerous: attack of the other side’s nuclear forces on the ground before they can be launched, called “counterforce” attack. It is this mission that requires that missiles be kept on frightening, ready-to-launch status at all times, and it tightly ties the size of the two arsenals to each other. Counterforce fools us into thinking that nuclear weapons are what save us from nuclear weapons, making further nuclear reductions impossible.

It will be politically difficult to ask either the United States or Russia to give up the ability to reduce the devastation of a possible future nuclear attack. But relinquishing counterforce will be easier for each side to accept if there is nothing to shoot at on the other side. The organizing principle of future US-Russian arms control should be coordinated reduction in the ability to strike the other’s vulnerable weapons along with negotiated reductions in the vulnerability of the remaining weapons. Better to negotiate weapons away on both sides in peacetime than blow them up in a nuclear war.

Without the counterforce mission, what is left to nuclear weapons is what everyone claims they are for — deterrence. Deterrence by retaliation is pretty straightforward: In response to some possible action the nation doesn’t like, it has to be able to threaten enough pain to make that action seem to cost more than it is worth. With the stakes in play today between the United States and Russia, the numbers of nuclear weapons needed to meet that goal are tiny compared to current arsenals.

By abandoning counterforce and moving to a true deterrent force, the performance requirements for the weapons themselves can be relaxed, starting with the numbers but including alert rates, accuracy, reliability, and explosive power. Both sides could consider new basing schemes that previously would have been rejected out of hand, precisely because they did not allow high alert rates or counterforce capability. A true deterrent force might, for example, place missiles in tunnels deep under mountains or store warheads separately from their missiles or use slower intercontinental cruise missiles instead of fast ballistic missiles. Studies on future nuclear forces should include these innovative, new, safer basing systems, which would pack enough punch to deter, but not be useful in, a counterforce attack — particularly against an enemy arsenal that had greatly reduced its vulnerability to a first strike.

Designing nuclear forces for what they are claimed to be for — deterrence — will allow lower alert rates, lower total numbers, and safer, less vulnerable basing systems; and such designs will open the road to further deep reductions, leading eventually to the elimination of these dangerous, outmoded weapons.

Editor’s Note: This Op-Ed is based on an article that will appear in the January/February issue of the Bulletin of the Atomic Scientists, published by Sage.