WASHINGTON — President Obama said Monday that he was revamping American nuclear strategy to substantially narrow the conditions under which the United States would use nuclear weapons.
But the president said in an interview that he was carving out an exception for “outliers like Iran and North Korea” that have violated or renounced the main treaty to halt nuclear proliferation.
Discussing his approach to nuclear security the day before formally releasing his new strategy, Mr. Obama described his policy as part of a broader effort to edge the world toward making nuclear weapons obsolete, and to create incentives for countries to give up any nuclear ambitions. To set an example, the new strategy renounces the development of any new nuclear weapons, overruling the initial position of his own defense secretary.
Mr. Obama’s strategy is a sharp shift from those of his predecessors and seeks to revamp the nation’s nuclear posture for a new age in which rogue states and terrorist organizations are greater threats than traditional powers like Russia and China.
It eliminates much of the ambiguity that has deliberately existed in American nuclear policy since the opening days of the cold war. For the first time, the United States is explicitly committing not to use nuclear weapons against nonnuclear states that are in compliance with the Nuclear Nonproliferation Treaty, even if they attacked the United States with biological or chemical weapons or launched a crippling cyberattack.
Those threats, Mr. Obama argued, could be deterred with “a series of graded options,” a combination of old and new conventional weapons. “I’m going to preserve all the tools that are necessary in order to make sure that the American people are safe and secure,” he said in the interview in the Oval Office.
White House officials said the new strategy would include the option of reconsidering the use of nuclear retaliation against a biological attack, if the development of such weapons reached a level that made the United States vulnerable to a devastating strike.
Mr. Obama’s new strategy is bound to be controversial, both among conservatives who have warned against diluting the United States’ most potent deterrent and among liberals who were hoping for a blanket statement that the country would never be the first to use nuclear weapons.
Mr. Obama argued for a slower course, saying, “We are going to want to make sure that we can continue to move towards less emphasis on nuclear weapons,” and, he added, to “make sure that our conventional weapons capability is an effective deterrent in all but the most extreme circumstances.”
The release of the new strategy, known as the Nuclear Posture Review, opens an intensive nine days of nuclear diplomacy geared toward reducing weapons. Mr. Obama plans to fly to Prague to sign a new arms-control agreement with Russia on Thursday and then next week will host 47 world leaders in Washington for a summit meeting on nuclear security.
The most immediate test of the new strategy is likely to be in dealing with Iran, which has defied the international community by developing a nuclear program that it insists is peaceful but that the United States and its allies say is a precursor to weapons. Asked about the escalating confrontation with Iran, Mr. Obama said he was now convinced that “the current course they’re on would provide them with nuclear weapons capabilities,” though he gave no timeline.
He dodged when asked whether he shared Israel’s view that a “nuclear capable” Iran was as dangerous as one that actually possessed weapons.
“I’m not going to parse that right now,” he said, sitting in his office as children played on the South Lawn of the White House at a daylong Easter egg roll. But he cited the example of North Korea, whose nuclear capabilities were unclear until it conducted a test in 2006, which it followed with a second shortly after Mr. Obama took office.
“I think it’s safe to say that there was a time when North Korea was said to be simply a nuclear-capable state until it kicked out the I.A.E.A. and become a self-professed nuclear state,” he said, referring to the International Atomic Energy Agency. “And so rather than splitting hairs on this, I think that the international community has a strong sense of what it means to pursue civilian nuclear energy for peaceful purposes versus a weaponizing capability.”
Mr. Obama said he wanted a new United Nations sanctions resolution against Iran “that has bite,” but he would not embrace the phrase “crippling sanctions” once used by Secretary of State Hillary Rodham Clinton. And he acknowledged the limitations of United Nations action. “We’re not naïve that any single set of sanctions automatically is going to change Iranian behavior,” he said, adding “there’s no light switch in this process.”
In the year since Mr. Obama gave a speech in Prague declaring that he would shift the policy of the United States toward the elimination of nuclear weapons, his staff has been meeting — and arguing — over how to turn that commitment into a workable policy, without undermining the credibility of the country’s nuclear deterrent.
The strategy to be released on Tuesday is months late, partly because Mr. Obama had to adjudicate among advisers who feared he was not changing American policy significantly enough, and those who feared that anything too precipitous could embolden potential adversaries. One senior official said that the new strategy was the product of 150 meetings, including 30 convened by the White House National Security Council, and that even then Mr. Obama had to step in to order rewrites.
He ended up with a document that differed considerably from the one President George W. Bush published in early 2002, just three months after the Sept. 11 attacks. Mr. Bush, too, argued for a post-cold-war rethinking of nuclear deterrence, reducing American reliance on those weapons.
But Mr. Bush’s document also reserved the right to use nuclear weapons “to deter a wide range of threats,” including banned chemical and biological weapons and large-scale conventional attacks. Mr. Obama’s strategy abandons that option — except if the attack is by a nuclear state, or a nonsignatory or violator of the nonproliferation treaty.
The document to be released Tuesday after months of study led by the Defense Department will declare that “the fundamental role” of nuclear weapons is to deter nuclear attacks on the United States, allies or partners, a narrower presumption than the past. But Mr. Obama rejected the formulation sought by arms control advocates to declare that the “sole role” of nuclear weapons is to deter a nuclear attack.
There are five declared nuclear states — the United States, Britain, France, Russia and China. Three states with nuclear weapons have refused to sign — India, Pakistan and Israel — and North Korea renounced the treaty in 2003. Iran remains a signatory, but the United Nations Security Council has repeatedly found it in violation of its obligations, because it has hidden nuclear plants and refused to answer questions about evidence it was working on a warhead.
In shifting the nuclear deterrent toward combating proliferation and the sale or transfer of nuclear material to terrorists or nonnuclear states, Mr. Obama seized on language developed in the last years of the Bush administration. It had warned North Korea that it would be held “fully accountable” for any transfer of weapons or technology. But the next year, North Korea was caught aiding Syria in building a nuclear reactor but suffered no specific consequence.
Mr. Obama was asked whether the American failure to make North Korea pay a heavy price for the aid to Syria undercut Washington’s credibility.
“I don’t think countries around the world are interested in testing our credibility when it comes to these issues,” he said. He said such activity would leave a country vulnerable to a nuclear strike, and added, “We take that very seriously because we think that set of threats present the most serious security challenge to the United States.”
He indicated that he hoped to use this week’s treaty signing with Russia as a stepping stone toward more ambitious reductions in nuclear arsenals down the road, but suggested that would have to extend beyond the old paradigm of Russian-American relations.
“We are going to pursue opportunities for further reductions in our nuclear posture, working in tandem with Russia but also working in tandem with NATO as a whole,” he said.
An obvious such issue would be the estimated 200 tactical nuclear weapons the United States still has stationed in Western Europe. Russia has called for their removal, and there is growing interest among European nations in such a move as well. But Mr. Obama said he wanted to consult with NATO allies before making such a commitment.
The summit meeting that opens next week in Washington will bring together nearly four dozen world leaders, the largest such gathering by an American president since the founding of the United Nations 65 years ago. Mr. Obama said he hoped to use the session to lay down tangible commitments by individual countries toward his goal of securing the world’s nuclear material so it does not fall into the hands of terrorists or dangerous states.
“Our expectation is not that there’s just some vague, gauzy statement about us not wanting to see loose nuclear materials,” he said. “We anticipate a communiqué that spells out very clearly, here’s how we’re going to achieve locking down all the nuclear materials over the next four years.”