By any reasonable measure the quarter-century-old nuclear Non-Proliferation Treaty has been a historic achievement, clearly the most inclusive and effective international arms control effort ever undertaken.
The NPT has been the primary legal instrument for keeping the five declared nuclear-weapons states--the United States, Britain, China, France and Russia--from transferring any nuclear explosive devices or technology to any other state. With a few exceptions its additional priority of barring non-nuclear-weapons states from seeking nuclear arms has also been met. Where deception and cheating have been carried out--notably by Iraq and North Korea--the pact's enforcement machinery has helped make exposure possible, forced verifying inspections and opened the way for U.N. actions leading to sanctions.
Without the NPT it's almost certain that an uneasy world would today be faced with a far larger number of nuclear states. The NPT has been an agreement that can honestly be said to have changed the course of history. Its success argues powerfully for its indefinite extension.
Achieving that extension is the chief goal of the United States during the current NPT conference in New York, being attended by the 178 signers of the treaty. In this it is backed by Britain, France and Russia. But China, the fifth declared nuclear power, which joined the NPT only in 1992, has sent uncertain signals about its policy. China now suggests that while it wouldn't necessarily oppose indefinitely extending the pact neither would it object simply to renewable 25-year extensions. What's the distinction? By approving the finite term option, China places itself on the side of various nonaligned states, led by Indonesia, Iran and Mexico, that want to allow for possible termination of the treaty. Why? By keeping open the possibility that the treaty would eventually expire and so remove a key barrier to other countries acquiring nuclear weapons, they seek to pressure the declared nuclear powers to further reduce their arsenals.