What's the value of a nuclear warhead today? Not the monetary value, but as a deterrent?

Nuclear explosions are frightfully destructive, and that's the point: to inspire fear, to deter an adversary. Atomic bombs still appeal to some nations and terrorists, making proliferation a constant risk. Fortunately, there are fewer nuclear warheads in the world than during the Cold War; down from about 60,000 to about 22,000 today, most of which remain in the United States and Russia. But the deterrent value of the arsenals isn't what it used to be. Both the U.S. and Russia face new threats -- terrorism, proliferation, economic competition, pandemics -- for which these long-range or strategic nuclear weapons are of little value.

Another group of bombs which have lost their purpose are the battlefield or tactical nuclear weapons, originally created during the Cold War to deter a massive land invasion in Europe. NATO has between 150 and 200 B-61 gravity bombs in Belgium, Italy, Germany, the Netherlands and Turkey, fewer than the thousands of weapons based in Europe during the superpower confrontation. Today, Russia has an estimated 2,000 useable tactical nuclear weapons, although it is not clear precisely how many nor where they are located.

Why are they still deployed? Russia has its own calculus; more about that below. But for NATO, the argument made by some is that these weapons have symbolic value, showing that non-nuclear members are sharing in the alliance defense burden.

Yet by many accounts, these nuclear bombs have no military utility. Where would they be dropped? The war plans of the Cold War are defunct. Our modern nuclear-tipped missiles are plenty accurate and sufficient for any future contingency or target.

In recent years, influential experts, politicians and diplomats have called for bringing this last arsenal of tactical nuclear weapons back from Europe to the United States. Now, former senator Sam Nunn, the Georgia Democrat and one-time chairman of the Senate Armed Services Committee, has joined them.

Nunn has often told the story of his visit to Europe as a young senator in 1974. At a U.S. tactical nuclear weapons base in Germany, he was shown the warheads and reassured by the commanders that all the weapons were secure. On leaving, a sergeant shook his hand and slipped Nunn a piece of paper, which suggested that Nunn come around later to the barracks to meet the troops guarding nuclear warheads.

That night, Nunn and his staff director, Frank Sullivan, went to the barracks. The sergeant and “three or four of his fellow sergeants related a horror story to me,” Nunn recalled. “A story of a demoralized military after Vietnam. A story of drug abuse. A story of alcohol abuse. A story of U.S. soldiers actually guarding the tactical nuclear weapons while they were stoned on drugs. The stories went on and on for over an hour.” Deeply worried about what he had heard, Nunn reported it to then-Defense Secretary James Schlesinger immediately on return to the United States.

The experience left a deep impression on Nunn -- it came to mind in those chaotic weeks after the failed coup in the Soviet Union in 1991, as the country stumbled toward breakup, and led Nunn to co-author the Nunn-Lugar legislation on cooperative threat reduction. It has come to the forefront again in a new essay by Nunn seeking action on the remaining tactical nuclear weapons still in Europe.

Nunn suggests that at NATO's planned summit in Chicago next May, the goal should be set of returning all the West's tactical nuclear weapons to the United States within five years. Nunn makes a series of additional recommendations for intensifying talks with Russia about security issues such as missile defense and conventional weapons. But what I found most interesting was that Nunn has thrown his weight behind the idea that the tactical nuclear weapons are obsolete.

Nunn has long been worried about the threat of nuclear terrorism, enhanced by the relatively small size and portability of these weapons. He says that "to persist in maintaining U.S. tactical nuclear weapons in Europe for another decade--in the absence of any real military or political utility--is more of a security risk than asset to NATO, given the nontrivial risk of a terrorist attack against a NATO base with nuclear weapons. The same is also true for Russia." (All the former Soviet weapons were pulled back to Russia at the end of the Cold War.)

Nunn says "there is scant support for the military utility of these weapons--no matter what the contingency." He adds, "If U.S. tactical nuclear weapons in Europe have virtually no military utility, it is hard to argue they have any appreciable value as a real deterrent." Nunn's essay is one of ten published in a new report by the Nuclear Threat Initiative, "Reducing Nuclear Risks in Europe: A Framework for Action." The report can be found here.

A somewhat different view prevails in Russia, where tactical nuclear weapons are seen as a useful complement to conventional or non-nuclear military forces, which are declining. Eugene Miasnikov of the Center for Arms Control, Energy and Environmental Studies in Moscow laid out the Russian perspective in a recent paper.

Miasnikov writes that the argument is being made more and more often in Russia that tactical nuclear weapons have a military role to play. Russia's leaders, he says, worry about "emerging dangers from NATO expansion, unrest in the Middle East and … South Asia and [the] growing economic and military potential of China. These dangers are seen as having potential to evolve into threats to Russia. Therefore, the Russian military [has been] given a task to prepare for scenarios that assume specific military missions for [non-strategic nuclear weapons]. These scenarios include not only naval nuclear weapons but also the weapons for other military services--the Air Forces, Air Defense and Ground Forces."

Tactical nuclear weapons are subject to no international treaties, no verification or data exchanges between Russia and the West. Miasnikov says that Russia is in no hurry to change that:

It is well known that the Russia’s strategic forces are shrinking. Its conventional forces are also becoming smaller in size even more rapidly. In spite of increase in its budget, the Russian military is unable to replace aged armaments with modern weapons. Results of military reforms carried out for the last twenty years have not lead to creation of a smaller but more capable military forces that the Russia’s leadership foresaw, as, in particular, the conflict with Georgia demonstrated in 2008….Russia’s leadership puts high stakes on retaining highly survivable nuclear deterrent capability. Building up strategic forces is an expensive way to pursue such a goal. Decreasing transparency is a much cheaper alternative. For these reasons there is a little interest on the Russian side toward increasing transparency of its military forces, and in particular – transparency of its non-strategic nuclear arms. In fact, the trend is opposite.

Miasnikov urges change from the status quo. He proposes a two-stage process to improve transparency of both Russian and U.S. tactical arsenals. It would start with something very simple: an exchange of data. How many are there, and where? With both the United States and Russia in presidential election cycles, my guess is there won't be any action soon. But when the political season is over, Nunn and Miasnikov have offered valuable ideas for how to make progress on this lingering problem. As Nunn writes, "This is a difficult web to untangle, but we must begin."

Further reading on this topic:

• Malcolm Chalmers and Simon Lunn, "NATO's Tactical Nuclear Dilemma," Royal United Services Institute, Occasional Paper, March 2010. 
• Daryl G. Kimball, "Strategic Choices on Tactical Weapons," Arms Control Today, Vol. 41, No. 9, November, 2011, p. 4.
• Robert S. Norris and Hans M. Kristensen, "U.S. Tactical Nuclear Weapons in Europe, 2011," Bulletin of the Atomic Scientists, 67(1)64-73.
• Hans M. Kristensen, "B61 LEP: Increasing NATO Nuclear Capability and Precision Low-Yield Strikes," FAS Strategic Security Blog.