Obama must decide degree to which U.S. swears off nuclear weapons

"The United States can't go around and ask others to give up their nuclear weapons while we maintain a list of official purposes for our nuclear weapons" that necessitate a large arsenal, said Jan Lodal, a senior Defense Department official in the Clinton administration.

The review comes as the U.S. military's precision guided conventional weapons have gained such accuracy that they can handle many threats assigned to nuclear weapons in the past.

Allies are split

But U.S. allies are divided about Obama's vision. New governments in Germany and Japan have embraced it, but some nations are more skeptical. "A country like ours, with a very special experience with its own history, we are maybe more cautious than some other countries," said Petr Kolar, the Czech ambassador, referring to past Soviet domination.

Kolar said big policy changes such as promising not to use nuclear weapons first in a crisis could embolden other nuclear-armed powers. "My personal perspective is . . . we shouldn't actually lose the instruments we so far have," he said. "What's the change that would be gained by that?"

Another European ambassador said the nuclear review broke ground in even contemplating such a pledge. But he said it was unlikely while NATO was engaged in a major study of its strategy, due out this fall.

Pentagon officials worry that allies such as Japan or Turkey could decide to develop their own nuclear weapons if they thought U.S. protection wasn't assured. Skeptics -- both Democrats and Republicans -- also question whether pledges to limit the U.S. nuclear role would have the impact claimed by proponents, because foes probably wouldn't believe such assertions. "We're better off when we communicate that all options are on the table," said Thomas Mahnken, a senior Defense Department official in the Bush administration. "As a practical matter, they are."

More than two dozen Democrats, led by Sen. Dianne Feinstein (Calif.), chairman of the intelligence committee, have pressed Obama to adopt language saying the "sole" or "only" purpose of U.S. nuclear weapons is deterrence. It would not prevent the U.S. government from using a weapon first but would deemphasize that option in planning.

The Bush administration's 2001 Nuclear Posture Review pledged to reduce the Cold War role of nuclear weapons. But it discussed planning to build new types of "bunker-buster" warheads. It also proposed developing the U.S. nuclear stockpile based not on the current threat posed by potential enemies but on their future capability to carry out nuclear, chemical or biological attacks.

As part of his declaratory policy, Obama will have to consider whether to break with the Bush and Clinton administrations' studied ambiguity about whether the United States would use nuclear weapons to respond to chemical or biological attacks planned by non-nuclear countries.

The president is expected to adopt that change, but with an important caveat, officials said. The new policy would drop that threat only for countries in compliance with the Non-Proliferation Treaty, and thus not working on their own bomb.

Leading by example

The immediate effect of such a policy would be limited, because the potential aggressors that most concern the United States are nuclear powers or accused treaty violators such as Iran. But the move could encourage other countries to stick to the rules of that pact, officials said.

"It would be a significant pulling back of the reach of the nuclear sword," said Hans Kristensen of the Federation of American Scientists.

One senior official said the review will "point to dramatic reductions in the stockpile" in coming years.

In particular, the review will push for beefing up the deteriorating U.S. weapons complex and nuclear labs so that the Pentagon can be more certain of its weapons' effectiveness, officials said. That shift will allow the Defense Department to get rid of some of the roughly 2,000 nuclear warheads it keeps as backups to its nearly 3,000 deployed weapons, officials said. There are also more than 4,000 older, inactive warheads in line to be dismantled.

It is not clear whether such reductions would be part of a formal treaty with Russia.