Shakier fingers on the nuclear buttons

Ever since the nuclear genie escaped from the bottle in 1945, we have been preoccupied with preventing this destructive power from being used. The solutions we have come up with can be boiled down to two.

The first is deterrence: you prevent the use of nuclear weapons against you by having enough of them yourself so that, even if the opponent attacks, you retain enough of them intact to retaliate with.

Theorists of deterrence did not necessarily envisage that this dire scenario would occur. Their logic was that if each side knew the other had enough survivable weapons, neither would attack: peace would flow from the balance of terror.

Deterrence has been roundly criticised, from the left and the right, but it has worked. No matter how deep the hatred between the former Soviet Union and the United States, the Soviet Union and China, China and the United States or India and Pakistan, none of these pairs has been involved in a nuclear war.

We've had nuclear weapons for over half a century now, so that's not a bad record – indeed, it's miraculous.

The second response to the nuclear menace has been non-proliferation policies. These are based on the assumption that if the number of countries with nuclear weapons increases, so will the statistical probability of the weapons being used; it's not unlike the reasoning of gun-control advocates.

But here too we have been remarkably successful. The know-how for building nuclear weapons has become widespread. Yet after more than 50 years, only a handful of states have them: the five permanent members of the UN Security Council plus India, Pakistan, Israel and, apparently, North Korea. That may be too high a number, but it could have been – and by all rights should have been – a lot higher. The 1968 Nuclear Non-proliferation Treaty is largely what has kept the nuclear club small.

Now, however, we face a totally different problem, and it can't be solved with the old standbys of deterrence and non-proliferation. This new situation could be called "nuclear fragmentation" – the sudden breakup because of civil war or revolution of countries possessing nuclear weapons.

Our first experience with the fragmentation problem was the unexpected collapse of the Soviet Union in 1991.

The demise of a totalitarian system was a good thing, but the dissolution of a union with tens of thousands of nuclear weapons was a not-so-good thing. We're still coping with the consequences.

Now, poverty-stricken Russia's nuclear installations are often guarded by demoralised and poorly paid staff.

Worries abound that organised crime rings and terrorists will steal Russia's nuclear weapons or fissile materials. European police have intercepted smugglers sneaking nuclear materials from the former Soviet Union more than once.

Yet the Soviet Union is not a unique case of the fragmentation problem, which has become worse. That is because there are several countries now that either have nuclear weapons or are trying to build them and that are at risk of breaking apart, including Pakistan, North Korea and Iran.

Iran doesn't have nuclear weapons yet, but there is a danger that it could get them, thanks to Russian-built nuclear reactors. And change is in the wind.

The bottom line is that our current tools to deal with nuclear threats – deterrence and non-proliferation – are inadequate to cope with the new problem of nuclear fragmentation. We must start thinking creatively about this new nuclear danger – and soon – if we want appropriate solutions.

The writer is a fellow at the Council on Foreign Relations and a professor of international relations at Lehigh University, USA.