Singapore ? President Barack Obama and other world leaders agreed today that next month’s much-anticipated climate change summit will be merely a way station, not the once hoped-for end point, in the search for a worldwide global warming treaty.

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 struggling 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. Addressing the Asia-Pacific Economic Cooperation forum later, Obama talked of the need to limit greenhouse-gas emissions “in Copenhagen and beyond.”

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.

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 show in Copenhagen.

It was unclear today whether he would make the trip.

Obama arrived late Saturday night in Singapore for the annual 21-nation APEC summit that had begun without him early that morning.

But on trade, he said the U.S. would engage with nations in a Trans Pacific free-trade partnership to shape a new regional agreement, a move seen as crucial to creating a possible Asia-Pacific free trade zone.