The trouble with zero

Last week,Obama had the tough task of trying to coax Pakistans president,Asif Ali Zardari,and the Afghan president,Hamid Karzai,into a more cooperative relationship and a more determined fight against the Taliban and Al Qaeda.

Yet even as the allure of disarmament grows,the obstacles seem as daunting as ever. Going to zero,as the nuclear cognoscenti put it,is a deceptively simple notion; just about everyone who knows nuclear weapons agrees it would be wickedly difficult to achieve.

Obama acknowledges that getting to zero wont be easy. The goal will not be reached quicklyperhaps not in my lifetime, he declared last month in Prague. It will take patience and persistence.

The new appeal of an old idea that long seemed quixotic is driven by the rise of new nuclear threats that in some ways make the nuclear equation more ominous and volatile than during the cold war,even though there are far fewer weapons now. Obama said it himself in Prague: In a strange turn of history,the threat of global nuclear war has gone down,but the risk of a nuclear attack has gone up.

Nuclear conflict between the United States and the Soviet Union was a prospect so harrowing that American and Soviet leaders recognised it was untenable,even as their generals planned for Armageddon. They possessed some 70,000 nuclear warheads between them in the 1980s,but the weapons were under firm control and neither side dared risk the retaliation that a first strike would draw. The balance of terror,in effect,neutralized nuclear weapons.

The dynamic today is much less stable,and more difficult for the US to manage,as the turbulence in Pakistan shows. As the nuclear club expands,the security of weapons and technology diminishes.

Faced with these dangers,Obama is banding with fellow leaders like President Dimitri Medvedev of Russia and Gordon Brown,the British prime minister,to push for a series of steps to reduce nuclear threats in the near term,while preparing ground for the eventual elimination of nuclear weapons.

The Obama administration and other advocates favor a reduction in American and Russian nuclear arsenals,to be followed by talks that include nations with smaller nuclear arsenals,like China. They want the United States Senate to ratify the 1996 Comprehensive Test Ban Treaty; would strengthen the 1968 Nuclear Non-Proliferation Treaty; and would seek an accord to verifiably ban the production of fissile materials intended for use in nuclear weapons.

Sam Nunn,the former chairman of the Senate Armed Services Committee,likens such steps to building a base camp that offers a vantage point from which the summit is visible and the final ascent to the mountaintop is achievable. It is an audacious agenda,but as alarm about nuclear threats rises,the chances of success seem to be growing,at least for some interim steps.

Past efforts have foundered. A 1946 plan named after the American financier Bernard Baruch died partly because its scheme to have a powerful international agency control nuclear technology required the five permanent members of the United Nations Security Council to give up their veto power on some nuclear matters. The Nuclear Non-Proliferation Treaty,41 years old now,has proved ineffectual in moving the world toward nuclear disarmament.

Ronald Reagan and Mikhail Gorbachev briefly considered eliminating nuclear weapons,during their 1986 summit meeting in Reykjavik,Iceland. The idea died when Mr. Reagan refused to abandon his missile defence programme.

Gorbachev,still pushing hard for nuclear disarmament 23 years later,co-hosted an international conference on nuclear issues in Rome last month,a few weeks after Obama was in Prague. Gorbachev noted that nuclear disarmament would be untenable to many nations if it left America with overwhelming superiority in conventional military forces. That is one of the biggest potential sticking points.

Dismantling Americas nuclear deterrence strikes many defence experts as unwise,if not suicidal. They ardently believe that nuclear weapons have made global war less likely.

They also suggest that the goal of eliminating nuclear weapons is a distraction from more modest but significant steps to reduce nuclear threats. To counter such concerns,Obama promised that as long as nuclear weapons exist,America would maintain a safe,secure and effective arsenal to deter any adversary and defend allies.

If arsenals are drastically reduced,the next steps toward abolition could be even trickier. Since scientific and engineering knowledge cannot be expunged from mankinds memory,the potential to build weapons will always exist.

Philip Taubman is writing a book on nuclear threats