Currently, there are between 20,000 and 30,000 nuclear weapons in the world [1, 2]. Of these, over 1,500 are deployable by the two largest nuclear weapons states, the U.S. and Russia .
We often hear how a world without nuclear weapons will enhance global security and safety and that we are on our way to a goal of a world without them. As put forward by President Obama in his 2009 speech in Prague, the U.S. is committed to a world “free of nuclear weapons.” However, President Obama admitted this goal might be many years away and possibly not feasible in his lifetime.
Though most of us have heard about the inherent dangers of large numbers of nuclear weapons, there is a flip side to this argument that we rarely (if ever) hear.
What are the possible problems with moving to low numbers of or eventually zero nuclear weapons?
With very low numbers of weapons globally, adding just a few more weapons to its arsenal would instantly give a country much more power over a potential adversary. Thus, some experts believe that very low numbers of nuclear weapons are fundamentally unstable, with zero as the most unstable.
For example, if two great powers faced each other with similarly-sized conventional forces, each opponent would have roughly the same power and could stop an attack or counter-attack. There would be little motivation to strike. However, once one side possesses one nuclear weapon, the stakes raise enormously. Now the possessor of the weapon has a huge advantage and an incentive to strike first before the opponent can nullify this advantage with their own nuclear weapon. Conversely, if two powers are facing each other with a large force of nuclear weapons, additional weapons would have a much lower impact, as the opponent has enough power to retaliate in the event of a first strike. This idea is amplified with a large conventional force (the U.S) against a smaller conventional force (like North Korea or Iran). A lesser force having a single nuclear weapon instantly creates parity or even an advantage over a larger conventional force. One can debate the merits of such a system for preserving the governments of weaker states, but it is hard to argue against that such a system would lead to instability.
Another issue that would be raised with very low numbers of weapons is that these weapons will be placed on the most survivable delivery systems a country has, such as submarines (U.S., Russia, U.K., France, Israel) or secret tunnel launching complexes (China). This means that the U.S.’s current counter-force strategy of targeting enemy weapons and industrial areas would be less effective and maybe even impossible if only a handful of weapons exist with a small industrial base to support them. The U.S. would need to change from a counter-force strategy (targeting military forces) to a counter-value strategy (targeting vulnerable, valuable areas). The U.S. would need to deliberately target the most valuable portions of an enemy country – population centers. In the past, the U.S. has chosen to raze enemy cities in times of war while trying to destroy military or industrial infrastructure. With a shift to a counter-value strategy, we would have to target cities for the very reason that they are filled with millions of people.
The opportunity presented by large reductions in the U.S. and Russian nuclear arsenals may lead other countries to build more weapons in order match the now reduced strength of the current nuclear powers. With the current size of the U.S. and Russian nuclear arsenals, some experts suggest that other nuclear powers are deterred from building a large arsenal, as they feel they cannot catch up without a great economic cost. Unless all nuclear powers bring down their numbers proportionally and in unison, there is a possibility that some states could try to build more weapons in order to gain an advantage over states that are reducing their nuclear weapons stockpiles.
Also, if the U.S. lowers the numbers of weapons in its arsenal, our non-nuclear allies might reconsider our capabilities or resolve, and would pursue nuclear weapons themselves. The assurances that the U.S. has made to defend allies against nuclear and conventional attack were made to deter the Soviet Union in Europe and to ensure that smaller nations did not feel obligated to develop their own nuclear weapons. This defensive umbrella is one of the reasons why many nations, including South Korea and Japan, have not developed nuclear weapons, even though they have all the capabilities and resources to do so.
Lastly, nuclear weapons are hard to find. The nuclear weapons of modern arsenals are easily carried on attack aircraft. Showing a potential adversary that a large number of nuclear weapons have been decommissioned and destroyed is difficult without intrusive inspections of nearly all military facilities. Most nations, including the U.S. and Russia, would likely refuse to allow such inspections.
So if trying to ban nuclear weapons is not only difficult (as can be seen with North Korea and Iran) but also potentially dangerous, what can be done instead?
The solution that would be most effective, yet hardest to achieve, is to deal directly with the security concerns that states have with one another. If states no longer feel threatened by one another, they would have a reduced incentive to build more than a handful of nuclear weapons.
However, this strategy alone will not remove the political aspect of nuclear weapons. Many states see these weapons as great symbols of power and prestige. Additionally, regimes can use weapons as tools to hold onto power, even if the security situation does not demand building a nuclear weapon.
Nuclear weapon states can gradually reduce their nuclear weapons together. Russia and the U.S. are already doing this through the New START Treaty, which went into effect in February 2011. If they are able to lower their stockpiles to several hundred nuclear weapons each, then other official nuclear powers could be invited to negotiate even lower numbers together. As long as a strong enough verification mechanism exists (modeled on the existing START treaties), then the nuclear powers can confirm that no weapon state is cheating the agreement and lower numbers of weapons could be achieved. However, once the level of weapons gets low enough, nuclear powers outside of the NPT (Non-proliferation Treaty), such as Pakistan, India, and possibly Israel, will need to be brought to the table. In the long run, a strategy like this may be effective down to lower numbers than currently exists, but it would not deal with the states that only have a handful of weapons and would not convince them give them up weapons without fundamental changes in their security.
It is clear that without a large and very intrusive inspection regime, many states would doubt their adversaries’ claims of reduced numbers of nuclear weapons. Also, as lower numbers are achieved and larger numbers of states will need to be brought into discussions about reducing the numbers of nuclear weapons, reaching consensus will become more difficult.
A potentially safer and less destabilizing route may be to begin banning delivery systems of nuclear weapons, starting with ballistic missiles. Without the means to very quickly deliver nuclear weapons, the weapons are much less useful to states. There is also precedent for this type of action, as the U.S. and the Soviet Union banned entire classes of missiles during the Cold War (short and medium range ballistic missiles). While many critics would argue that this would give the U.S. a great advantage with its air power, the most advanced in the world, it would still greatly increase decision makers’ reaction time when using nuclear weapons. With a missile, the reaction time that leaders have is minutes. They must decide to fire now, because enemy missiles may be only minutes away. With bombers this time window, increases to hours. This would greatly reduce the threat of an accidental launch or a misinterpretation of a threat and give political leaders extra time to come to a solution before the weapons can reach their targets.
It is also easier for adversarial countries to inspect missile facilities (missile fields, submarine bases, etc.), as they are large and easy to identify. This would greatly reduce the intrusiveness of inspections, thereby making this type of regime an easier sell in the political realm.
Eliminating nuclear weapons will most likely be more difficult and complex than it first seems. The gradual reduction in nuclear weapons is potentially destabilizing, and may send signals to both adversaries and allies that we are not serious about deterrence and ensuring global stability. Also, an intrusive inspection regime that would be necessary to prove the elimination of nuclear weapons would be well beyond what nuclear armed states would allow. Instead of counting the numbers of small, easily concealable weapons and judging success or failure by how many warheads nations have, we should try a method that has already proven to be effective. We should start by reducing and eventually eliminating the delivery vehicles that states can use to rapidly destroy one another, without having time to think through a reaction.
So, will we ever get rid of nuclear weapons?
I believe, someday, we will. However, I do not think that we will do it by reaching a mutual agreement among nations because too much animosity exists. I think we will do it the way we have made other weapons obsolete, by creating even more advanced weapons. There is no shortage of historical examples for this trend. The gun replaced the bow and sword, and the tank replaced the horse. While agreements like the START Treaty may be large political and diplomatic accomplishments, what will make states eventually give up nuclear weapons is when an even more powerful weapon is created, and these more advanced weapons will do what all the disarmament treaties in the world cannot. It will “give us the means of rendering these nuclear weapons impotent and obsolete.” 
 Stockholm International Peace Institute June 7, 2011 report, http://www.sipri.org/media/pressreleases/2011/yblaunch11
 Greenpeace International, http://www.greenpeace.org/international/en/campaigns/peace/abolish-nuclear-weapons/the-vital-statistics/
 State Department, http://www.state.gov/www/global/arms/treaties/inf1.html
 Quote, Ronald Reagan.