Five years ago, it worked: The major nuclear powers produced a joint statement on ways to reduce the nuclear threat, helping bring a successful end to the 2000 conference to strengthen the nonproliferation treaty.
This time around, at the latest of the twice-a-decade treaty reviews, the going looks tougher in closed-door talks on a joint declaration.
"The situation has changed drastically in those five years," top Russian delegate Anatoly Antonov said Monday, as the monthlong global conference entered its final week with prospects dimming for significant arms-control initiatives.
At the 2000 conference, the five powers' endorsement of the 1996 nuclear test-ban treaty, for example, signaled to states without nuclear weapons that those with them were serious about eventual disarmament. That joint position contributed to a spirit of compromise that led to a consensus final document among the more than 180 treaty members, Antonov said.
But the gulf has widened since between Washington and other atomic-weapons states on such issues as the test ban, which Russia, Britain and France have ratified but the Bush administration rejects.
Under the Nuclear Nonproliferation Treaty, 183 nations renounce nuclear arms forever, in exchange for a pledge by five states - the United States, Russia, Britain, France and China - to move toward nuclear disarmament. Nonweapon states, meanwhile, are guaranteed access to peaceful nuclear technology.
The review conferences are intended to identify weaknesses in the 1970 pact and to win political commitments from member states to take steps to remedy them.
Far from the U.N. basement meeting rooms, the need for such steps is increasingly apparent.
European and Iranian negotiators meet Wednesday in Geneva to try to salvage talks in which the Europeans are asking Iran to back down from its uranium-enrichment program, which can produce both fuel for nuclear power plants and material for nuclear bombs.
In Asia, meanwhile, North Korea, which announced its withdrawal from the nonproliferation treaty in 2003, is pondering its next move in a slow-motion international showdown over its weapons plans.
The U.N. conference had bogged down for almost three weeks in bickering over the agenda. The United States insisted it focus on proliferation issues, meaning Iran and North Korea. But many non-weapons states want equal emphasis on the nuclear powers' obligations to eventually eliminate their arsenals.
At the 2000 conference, a consensus finally emerged accepting, among other things, "13 practical steps" toward disarmament, including activating the test-ban treaty and strengthening the treaty banning anti-ballistic missile systems.
Those steps were endorsed by the Clinton administration, but the incoming Bush administration rejected the test-ban pact and withdrew from the ABM treaty. Nonweapons states now want some reaffirmation of disarmament goals at the current conference, but the gap looks too wide, at a gathering where agreement must be unanimous, to produce significant consensus.
Antonov, the Russian Foreign Ministry's disarmament director, said a 2005 declaration by the five nuclear powers would be "necessary, first of all, to add momentum to the conference." But he then took note of the "drastic changes" since 2000 - differences over key elements in the arms-control picture.
"We're missing key disarmament agreements," he said, referring to rejected treaties, and "we're facing new nuclear defense systems that might undermine Russian defenses," a reference to the Bush administration's planned deployment of an anti-ballistic missile system.
When asked, U.S. delegation spokesman Richard Grenell declined to discuss details of the five-power talks. "We're hard at work and we're hopeful we'll be able to have a statement," he said.
CHARLES J. HANLEY, AP Special Correspondent