THE United States and Russia no longer point nuclear-tipped missiles at each other. But the end of the cold war has not meant that the threat of a nuclear attack somewhere in the world has disappeared.
Pondering what would have happened if the terrorists who attacked the World Trade Center had used an atomic weapon is a more-than-sobering exercise. Just 12 pounds of fissile material could have created an explosion the size of the Hiroshima blast.
Responsible governments worldwide need to place control of nuclear weapons and of the materials to build them at the very top of their agendas. As usual, the US must take a strong leadership position.
One crucial opportunity arrives April 17 when 170 nations gather at the UN to renew and, if possible, make permanent the 1970 Nuclear Non-Proliferation Treaty. The agreement is set to expire this year.
In it, nonnuclear states promise not to develop nuclear weapons; in exchange, the handful of declared nuclear states agree to assist nonnuclear nations in developing peaceful nuclear energy. And they pledge to work to eventually eliminate their own nuclear stockpiles.
Although the agreement may sound like a winning proposition all around, ratification is far from certain. Some nonnuclear nations argue the treaty freezes in place a permanent advantage for the nuclear powers. Some are already refusing to sign; others may insist they will only sign for a limited time period. Arms-control experts worry that a treaty with a time limit will encourage secret development of nuclear weapons because nations would be forced to prepare for the possibility of the treaty expiring.
This week the Clinton administration finally seemed to get this vital issue on its radar screen. As a sign of good faith to nonnuclear states, it extended its own moratorium on underground nuclear tests and took action to smooth the way for signing a Comprehensive Test Ban Treaty with the other nuclear states.
If the Senate can quickly ratify the Start II treaty, which slashes US and Russian nuclear arsenals, it will send another helpful signal.
Reducing the nuclear risk involves many other steps - strong export controls, vigilance against smuggling and terrorist groups, and reducing the production and availability of weapons-grade plutonium. But none is more important than continuing the Nuclear Non-Proliferation Treaty.