WASHINGTON — Secretary of State Hillary Rodham Clinton warned Wednesday that the United States may erect a "defense umbrella" over the Middle East if Tehran continues its nuclear program, a sign that the Obama administration is preparing for the reality of an Iranian bomb.
Clinton, appearing at a regional meeting in Thailand, also laid down a tough line on North Korea, declaring that the United States and the communist nation's neighbors will offer no new incentives for the Pyongyang government to return to nuclear disarmament talks.
"We do not intend to reward North Korea just for returning to the table, nor do we intend to reward them for actions they have already committed to, then reneged on," Clinton said after conferring with ministers of China, Russia, South Korea and Japan.
In raising the possibility of a "defense umbrella," Clinton insisted that she was not abandoning the current U.S. policy toward Iran, which involves a combination of diplomatic outreach and sanctions. Even so, her words suggested that U.S. officials are looking ahead in case the approach, which faces formidable obstacles, proves unsuccessful.
Although President Obama has pushed hard to draw the Islamic Republic to the negotiating table, some U.S. officials and many outside experts have doubts that outreach efforts will succeed. And the likely next step, an effort to organize tougher international economic sanctions, faces strong resistance from Russia, China and India.
Some senior figures in the Obama administration have suggested that the U.S. might have to live one day with the reality of an Iranian bomb.
Defense Undersecretary Ashton B. Carter wrote before joining the administration that if diplomacy failed, the fallback was a policy of "containment and punishment."
Gary Samore, the chief of nonproliferation at the National Security Council, wrote before Obama was elected that Iran would probably act like other nuclear-armed states and was not likely to give terrorists the bomb.
The United States offers extensive military equipment and commitments to a number of Middle Eastern countries, including Iraq and Saudi Arabia.
A "defense umbrella" suggests that the United States would promise to retaliate against any strike on the protected countries, a policy it follows for Japan and South Korea.
Clinton didn't say that the United States would offer the protection of a "nuclear umbrella." But James Dobbins, a former U.S. diplomat now with the Rand Corp., said that with the enormous U.S. conventional forces in the region, the United States probably wouldn't need such a promise to retaliate.
Although Clinton's words didn't necessarily indicate a policy shift, "they do suggest they're seriously considering the requirements of deterrence," Dobbins said.
Clinton's suggestion drew a quick reaction from the Israeli government, which feels threatened by Iran's nuclear program and has been pushing the U.S. and other countries to move aggressively to halt it.
Dan Meridor, Israel's minister of intelligence and atomic energy, told Israel's Army Radio: "I was not thrilled to hear the American statement from yesterday that they will protect their allies with a nuclear umbrella -- as if they have already come to terms with a nuclear Iran. I think that's a mistake."
Clinton said her goal was to convince Iran's leaders that the bomb would be of little benefit.
"We want Iran to calculate what I think is a fair assessment: that if the U.S. extends a defense umbrella over the region, if we do even more to support the military capacity of those in the Gulf, it's unlikely that Iran will be any stronger or safer, because they won't be able to intimidate and dominate, as they apparently believe they can, once they have a nuclear weapon."
Dobbins said Clinton's comments probably also were aimed at reassuring Iran's neighbors and convincing them that they do not need to build their own nuclear weapons if Tehran acquires the know-how.
There are wide fears that countries such as Egypt and Saudi Arabia would feel compelled to launch their own weapons programs if Tehran gained nuclear weapons capability.
Clinton said that Iran "faces the prospect, if it pursues nuclear weapons, of sparking an arms race in the region. That should affect the reality of what Iran intends to do."
Clinton's warning on North Korea was another sign that the administration is deeply reluctant to try to buy North Korea's participation in the 6-year-old six-nation disarmament talks, as past administrations have done, and is largely focusing on containing the proliferation of nuclear and missile equipment.
Both the Clinton and Bush administrations offered sweeteners for Pyongyang to resume talks. But Clinton insisted that the five countries presented a "united front" and that North Korea needed to undergo a "complete and irreversible denuclearization" before it will receive any additional rewards.
The chief U.S. goal in recent weeks has been to persuade other Asian countries to help enforce a United Nations resolution that calls for blocking shipments of banned weapons and halting international financing of North Korea's arms trade.
Clinton said that Russia, China, South Korea and Japan have agreed to cooperate in implementing the resolution.
Special correspondent Charles McDermid in Phuket, Thailand, contributed to this report.