The 192-nation climate conference beginning in three weeks in Copenhagen had originally been intended to produce a new global climate-change treaty. Hopes for that have dimmed lately. But comments by Obama and fellow leaders at a hastily arranged breakfast meeting here on the sidelines of an Asia-Pacific summit served to put the final nail in any remaining expectations for the December summit.
"There was an assessment by the leaders that it is unrealistic to expect a full internationally, legally binding agreement could be negotiated between now and Copenhagen which starts in 22 days," said Michael Froman, Obama's deputy national security adviser for international economic matters.
The prime minister of Denmark, Lars Loekke Rasmussen, the U.N.-sponsored climate conference's chairman, flew overnight to Singapore to present a proposal to the leaders to instead make the Copenhagen goal a matter of crafting a "politically binding" agreement, in hopes of rescuing some future for the badly off-track process.
A fully binding legal agreement would be left to a second meeting next year in Mexico City, Froman said.
Obama backed the approach, cautioning the group not to let the "perfect be the enemy of the good," Froman said. Obama and other leaders, including Chinese President Hu Jintao, expressed support for progress at Copenhagen. Froman said the Danish proposal would call for Copenhagen to produce "operational impact," but he did not explain how that would work or to what it would apply.
Despite the cooperative-sounding words, the two-year process of crafting a landmark new treaty has been marked by deep distrust between rich, developed nations like the U.S. and those in Europe, and poorer developing nations such as India, Brazil and China.
The developed nations hold that all countries must agree to legally binding targets to reduce heat-trapping gases. Developing countries say they can make reductions a goal but not a requirement, and they want more money from wealthy nations to help them make the transition.
How to bridge that gap has made a treaty elusive.
A major bill dealing with energy and climate in the U.S., a domestic priority of Obama's, is bogged down in the U.S. Senate with scant hope it would be completed by next month, giving the American president little to take to Copenhagen. Between that and the developments in Singapore, there may be little reason for Obama to travel to Copenhagen. White House aides had been saying privately that the outcome of talks during Obama's weeklong Asia trip, including a three-day visit to China that starts Sunday night, would help determine whether Obama might go.
Obama arrived late Saturday night in Singapore for the annual 21-nation Asia-Pacific Economic Cooperation forum. His focus was more on side meetings, including one later Sunday with Russian President Dmitry Medvedev where he hoped to nudge forward a major new arms-control pact. The two nations are in talks on a successor to a Cold War-era agreement that expires in December.
Obama also was sitting down with Indonesia's Susilo Bambang Yudhoyono, president of the world's largest Muslim nation and Obama's home as a boy.
And the president planned another milestone: joining a larger meeting that includes the leader of military-ruled Myanmar. Obama is sure to face criticism at home, particularly from conservatives, for doing so - a significant step up in his administration's new policy of "pragmatic engagement" that is a shift from years of U.S. isolation and sanctions.
Myanmar, also known as Burma, is a member of the 10-nation Association of Southeast Asian Nations, or ASEAN, and Obama is sitting in on their meeting. A U.S. president has never met with a leader of the Burmese junta, one of the world's worst human-rights offenders.
Despite the new engagement, the Obama administration has said that sanctions will not be lifted unless Burma's rulers make democratic progress, such as releasing opposition leader Aung San Suu Kyi, a Nobel Peace Prize laureate and democracy icon who has been under house arrest for most of the last two decades.
Obama aides as well as outside Asia experts have defended the administration's new gamble on Burma, even while admitting it may not succeed.
"One definition of insanity is to do the same thing over and over and expect a different outcome," said Jeffrey Bader, Obama's top Asia adviser.
Obama and Medvedev agreed in April to reach a new nuclear arms reduction treaty to replace and expand upon the Strategic Arms Reduction Treaty before it expires on Dec. 5. Later, in Moscow in July, they agreed further to cut the number of nuclear warheads each nation possesses to between 1,500 and 1,675 within seven years.
U.S. officials say the two nations now have agreed on the broad outlines of a new treaty, which might be signed during Obama's travels to Europe in early December to accept the Nobel Peace Prize.
Such an agreement would further Obama's promise to work toward a nuclear-free world, offering momentum for other arms-control and nonproliferation efforts.
"We are already taking steps to bring down our nuclear stockpiles in cooperation with the Russian government," Obama said during a news conference in Japan with Prime Minister Yukio Hatoyama.
A new treaty also could boost relations with Russia as Washington seeks its cooperation on issues including reining in Iran's nuclear ambitions.
Negotiators have agreed on the number of U.S. and Russian warheads, the number of delivery systems and what will count as a delivery system, officials said. The remaining issues involve how to verify that the each side is meeting the treaty's terms, they said.
Ben Rhodes, deputy national security adviser to Obama, suggested it wasn't likely the leaders would announce a breakthrough this week but that holding talks at such a high level while they are going on could help bring one about.
The existing START treaty, signed by Soviet President Mikhail Gorbachev and President George H.W. Bush in 1991, led each country to cut its nuclear warheads by at least one-quarter, to about 6,000. In 2002, Presidents Vladimir Putin and George W. Bush signed the Treaty of Moscow, which specified further cuts to between 1,700 and 2,200 operationally deployed warheads by 2012.
The U.S. now has about 2,200 such warheads deployed, compared to about 2,800 for the Russians.
Associated Press writers Desmond Butler in Washington and Charles Hutzler in Singapore contributed to this report.