Reporting from Washington — As thousands of activists rallied on the National Mall on Sunday for federal legislation to curb global warming, Obama administration officials and leading senators worked behind the scenes to rescue a climate bill that appeared close to flat-lining over the weekend.
By day's end, supporters said its prospects were brightening slightly, with the Republican coauthor of the legislation, Sen. Lindsey Graham of South Carolina, again discussing it with Sens. John F. Kerry (D-Mass.) and Joe Lieberman (I-Conn.).
Graham had backed away Saturday after months of negotiations because of a dispute with Senate Democratic leaders over the timing of votes on climate and immigration legislation. His move prompted Kerry and Lieberman to postpone the rollout of the climate bill, which had been scheduled for Monday.
After talking with Graham on Sunday morning, Kerry and Lieberman prepared to move ahead without him if necessary. But a Senate aide said they were increasingly optimistic that Graham would return. His presence adds the crucial imprimatur of bipartisanship to the bill, which is likely to stall without it.
Urgency ran high at the climate rally Sunday, which capped several days of celebrations to mark the 40th anniversary of Earth Day.
The rally featured a live performance by Sting and speeches by the Rev. Jesse Jackson and film director James Cameron, among others. It focused on prodding Congress to pass a bill to cut the greenhouse gas emissions that scientists blame for climate change.
"This is our problem," Stephen Schneider, a climatologist at Stanford University, told the crowd. "We have to get people to understand what scientists understand: Global warming is unequivocal."
In an animated speech, Jackson made what he called "a moral appeal" for environmentally friendly policies. "The scientists have given us warning; it's time to fight back," he said. "It's not too late for us. … Don't let them break your spirit."
Other speakers were lesser known but equally passionate.
"I know that every dollar we spend on foreign oil is another dollar that goes to [Iranian President Mahmoud Ahmadinejad] to spend on nuclear weapons and fund terrorism," said Rob Levinson, who described himself as a 20-year Air Force veteran. "It's time for climate and energy legislation now."
Most analysts consider Graham the key to the climate legislation's success. He has helped reach out to industry groups to try to enlist their support.
Perhaps most important, Graham is a rare Republican who is willing to work with President Obama and Democrats in crafting major legislation. The bill is expected to need several Republican votes to pass because Senate Democrats are not united.
Underscoring that importance, White House Chief of Staff Rahm Emanuel called Graham on Friday evening after hearing that Graham was concerned that Senate Majority Leader Harry Reid (D-Nev.) would bring an immigration bill to a vote before the climate bill.
Nevertheless, Graham stepped back from the climate talks Saturday, criticizing Reid and Obama.
White House staff reached out immediately to Graham, Kerry and Lieberman's staff, according to sources with knowledge of the situation who were not authorized to speak on the record. Obama's top climate advisor, Carol Browner, spoke repeatedly with Kerry and, late Saturday, with Lieberman.
The White House message was that Obama remained upbeat about the climate bill's chances and was committed to bringing Graham back to the process, sources said.
Reid's spokesman, Jim Manley, said in an interview that Reid had promised to bring the climate bill to a vote this year. He also said it was clear that "climate negotiations are much farther along than the immigration bill," meaning that climate "could be the first to come to the floor."
Graham's office did not return e-mails seeking comment. But environmentalists who spoke with Graham on Sunday said he was committed to the issue.
Fred Krupp, president of the Environmental Defense Fund, said it was up to Obama and Reid to salvage the negotiations.
"What we need here is leadership," Krupp said. "Specifically, it means the majority leader and the president getting engaged, meeting with senators and helping to round up 60 votes."
The underlying politics are complicated for everyone. Reid's imperiled reelection bid could hinge on Latino voters, who could be motivated to support him if he is linked to the immigration bill.
Graham has worked with Sen. Charles E. Schumer (D-N.Y.) to craft a bipartisan immigration bill. This month, Obama called several Republican senators to discuss immigration. A source with knowledge of the situation said the calls came at the request of Schumer and Graham.