The group, an offshoot of the so-called Gang of Six, is "practically sprinting" to get the bill officially introduced, one congressional aide said, and are working to add as many Republican supporters as possible. When the bill was unveiled on Wednesday night, it had picked up four Republicans in addition to the three that worked to develop it.
If all 49 Democrats support the bill, only four more Republicans would be needed to clear the 60 votes required to advance legislation in the Senate.
Even though the bill has already been rejected by the President and Republican leadership, the calculus is that with a standoff on government funding, Republicans will be pressed on why they walked away from a bipartisan deal with votes to pass it when the shutdown blame game begins.
Illinois Democratic Sen. Dick Durbin, one of the lead authors of the bill, met on Thursday morning with the House Problem Solvers Caucus, a bipartisan group of lawmakers who have sought a centrist deal on DACA as well, his office said. Building House support could answer White House chief of staff John Kelly's criticism
that the bill didn't have backing from both sides of Capitol Hill when it was brought to the President last week.
"It will be the basis of an agreement. Things will be added to it," said Republican Sen. Lindsey Graham of South Carolina. "The President outlined a way forward on Tuesday. This proposal follows that outline. We can make it a little bit better, maybe for both sides. I don't think there's a whole lot of room to move, but some."
Democrats' negotiating position got stronger on Thursday when Republican South Dakota Sen. Mike Rounds, who has backed the bipartisan immigration bill, announced he would not vote for a weeks-long short-term funding extension, saying good governance requires a long-term solution instead of short-term fixes.
Rounds joined Graham in his opposition. With other Republican fiscal hawks traditionally opposed to short-term continuing resolutions, the pressure is lifted off vulnerable Democratic senators up for re-election to vote for a funding deal that even a handful of Republicans aren't supporting.
The bill would offer a pathway to citizenship for eligible young undocumented immigrants who came to the US as children, allocate nearly $3 billion to a border wall and technology, limit sponsorship of family members by recipients of the program and reallocate diversity lottery visas to other immigration programs.
Advocates are optimistic that the tide has turned in Democrats' favor in recent days. They argue that the President's rejection of the bipartisan bill -- just days after he was televised telling lawmakers to bring him a deal and he would sign it -- combined with the news of Trump referring to certain countries in a disparaging way has only empowered Democrats to stand up.
"In the last 24 hours we've sensed a real shift from Republicans not believing Democrats are going to be resolute, to, 'Oh my god, Democrats are resolute and Republicans are joining in and we won't be able to pass the CR without negotiation,'" said Frank Sharry, a longtime immigration advocate with America's Voice Education Fund.