Senate Democrats struggled Monday to salvage a compromise climate change bill after Sen. Lindsey Graham (R-S.C.) walked away from the deal over the possibility of immigration reform taking center stage on Majority Leader Harry Reid’s (D-Nev.) agenda.

Sens. John Kerry (D-Mass.) and Joe Lieberman (ID-Conn.), who have worked with Graham on climate change for months, were hoping a Monday evening meeting with their erstwhile GOP collaborator would convince him to return to the fold.

David Wade, Kerry’s chief of staff, said Monday that Kerry “absolutely believes we can get around this roadblock, and many people inside the Senate and the administration are working overtime in good faith to make that happen. Frankly he’s been buoyed by the calls from inside and outside the Senate, from environmentalists as well as industry, not to lose momentum or risk losing an historic breakthrough on reform. Everyone knows this is the last, best chance to get the job done.”

However, Graham dimmed the prospect of reviving the deal even further Monday night, saying he wouldn’t get back on board unless Democrats pledged to take immigration legislation off the agenda for the year.

And a Republican aide familiar with the situation downplayed the likelihood that Monday’s meeting would bring Graham back to the table. “I wouldn’t read too much into that,” the aide said of the meeting, adding that it is the decision by Reid and Obama to move to immigration that has caused the rift. Kerry and Lieberman are “not the problem here.”

Nevertheless, Democrats including Reid remained hopeful.

Reid “is committed to trying to enact comprehensive clean energy legislation this session of Congress,” Reid spokesman Jim Manley said. “Doing so, however, will require strong, bipartisan support. Sen. Reid will continue to consult with Sen. Kerry about next steps and strategy, but given the amount of work that has already gone in to the this issue, it makes sense that climate change may go before immigration.”

Kerry, Lieberman and Graham had been scheduled to introduce their compromise bill Monday morning, and they had lined up support from business groups, environmentalists and union officials.

But in the wake of reports that Reid and Speaker Nancy Pelosi (D-Calif.) were contemplating moving immigration legislation before the climate bill, Graham balked. According to Democratic aides, by Friday Graham was clearly uncomfortable with the idea of rolling out the legislation without a commitment from Reid to not push immigration first, which Reid has refused to do.

On Saturday, Graham released a letter to stakeholders warning that, “Unless [Reid’s] plan substantially changes this weekend, I will be unable to move forward on energy independence legislation at this time.”

Reid responded with a statement assuring his colleagues that neither immigration reform nor climate change had precedent over the other.

“Immigration and energy reform are equally vital to our economic and national security and have been ignored for far too long,” Reid said in the statement.

But the damage had been done.

The collapse of the climate bill set off an intensive push by Kerry, Lieberman and their supporters to get the legislation back on track.

Kerry has spoken “several times in last 48 hours” with Reid and the White House, an aide to Kerry said, although the source did not immediately respond to a request for comment on what sort of assurances leadership had offered about whether the climate bill would move before immigration.

Lieberman also spoke with Reid about the climate legislation over the weekend, an aide said, adding the that conversation “was very positive about moving the bill forward.”

Appearing on MSNBC Monday, Lieberman predicted that the pushback from Graham would effectively put the climate bill on the front burner, where Lieberman thought it should be.

“I think that means we’re not going to get immigration reform done this year,” Lieberman said. “But we can still do energy and climate.”

A Lieberman aide said Monday afternoon that “based on discussions between members involved and the leadership” his boss remained optimistic the bill would “move forward,” but declined to comment on whether Graham had indicated a willingness to come back to the negotiating table or whether Democrats had begun to reach out to other Republicans.

A senior Democratic leadership aide expressed frustration at the situation, saying that while Reid has made no decisions about whether to move immigration legislation or a climate bill first, the climate bill was further along the legislative process and with some bipartisan support could have moved quickly. According to the leadership aide, it was Graham’s departure from the negotiations and not Reid’s desire to pass immigration reform that may doom climate change legislation.

“If we can get bipartisan support, we can move this quickly. Not this work period, but quickly,” the aide said.

A second Democratic aide took a more blunt view of the situation, saying that with election season heating up, the lack of bipartisanship generally in the Senate and the controversial nature of both issues, neither climate change nor immigration has any realistic chance of passing this year.

“The irony of all this is that you have the Hispanics and the environmentalists lining up to be the first to fail,” the aide said.