Despite its bipartisan pedigree, an immigration bill from the Senate’s “Gang of Six” appears unlikely to advance amid backlash from congressional Republicans and the White House.

GOP lawmakers are now placing all their hopes on a coalition of four House and Senate leaders to come up with a solution to address the pending end of the Deferred Action for Childhood Arrivals, a program that covers immigrants who come to the country illegally as children.

But tension remains high as negotiations continue.

Republican lawmakers and aides say two of their GOP colleagues — Sens. Lindsey Graham of South Carolina and Jeff Flake of Arizona — wasted time negotiating a deal they believe cannot get the votes necessary to pass either chamber and is opposed by the White House.

Along with Graham and Flake, the group includes Sens. Cory Gardner, R-Colo., Robert Menendez, D-N.J. and Michael Bennet, D-Colo., as well as Senate Minority Whip Richard J. Durbin of Illinois.

“I always thought gangs were formed when they could guarantee the vote threshold to get to 60. To me at least, if that’s really the way it’s used there’s not a baseline of votes to get there,” Sen. Thom Tillis, a North Carolina Republican who was initially working with the “Gang of Six” on the proposal, said. “We’ve had a week where we could have had the bipartisan meetings, figure out what the real gaps are. So it’s the time factor that I’m most concerned with.”

Watch: Booker Says DHS Secretary is ‘Complicit’

Graham defended his bill and said he hoped more people would view the proposal as legitimate.

“What’s dead on arrival is the idea we are going to fund the government without dealing with DACA,” he said. “I’m going to keep advocating for my proposal, it can always be made better.”

Flake also said he believes support for the measure will grow.

“This can get a vote. Bringing a bill that just has Republican support doesn’t do any good. This is the only game in town, this bipartisan bill,” he said.

Among the biggest complaints from opponents is the lack of long-term funding for border security, including a wall on the U.S.-Mexico border, in the current proposal. The measure would provide $1.5 billion in funding for the wall, according to a summary obtained by Roll Call. But that money would only be allocated for fiscal year 2018, forcing Congress to decide whether to reauthorize it and tee’ing up another immigration battle in 2019.

The six lawmakers are expected to introduce their legislation on Wednesday, but Senate Majority Whip John Cornyn, R-Texas, said it would not receive a vote in either the House or the Senate.

Adding to the bill’s troubles, Republicans say White House buy-in is paramount and Trump has already rejected the proposal.

“There are a lot of people on both sides of the aisle trying to get an outcome on DACA,” Senate Majority Leader Mitch McConnell, R-Ky., told reporters after the weekly GOP policy lunch on Wednesday. “An outcome involves the signature of the president of the United States. So what I’m waiting for in terms of making a decision on floor time is are we dealing with an issue that has a chance to become law.”

Not everyone thinks Graham and Flake are negotiating in the best interest of the GOP and the administration. Aides point to Flake’s speech on Wednesday blasting President Donald Trump after linking him to Joseph Stalin — the former dictator of the Soviet Union — as evidence that there was no strong desire in the group to meet the demands of the White House.

Senators say any and all input on the debate over DACA is helpful and believe the continued lobbying by Graham and Durbin — the bill’s two key sponsors — does not undermine the ongoing negotiations among House and Senate leaders. Several aspects of the Graham-Durbin proposal that enjoy bipartisan support could even serve as a basis for a final bill.

But there is some skepticism that Durbin, who is a member of that group, will negotiate in good faith while advocating for a separate proposal that Republican leadership has said is dead. Along with Durbin, the coalition includes Cornyn, House Majority Whip Kevin McCarthy of California and House Minority Whip Steny H. Hoyer of Maryland.

Members say discussions continue.

“We’re all highly motivated by the fact that come March 5 this program will no longer be available,” Cornyn said. “We’re all committed to getting to yes.”

The four leaders met on Wednesday and were joined by White House Chief of Staff John Kelly and White House Legislative Affairs Director Marc Short.

“The nature of the United States Congress is people propose bills,” Kelly said. “Right now, we’re just watching the legislative process work.”

Tillis said the smaller leadership group will brief a broader swath of Republicans and Democrats on their proposal in the coming weeks.

GOP lawmakers hope a deal is close and point to general agreement over many major aspects. Funding for the wall continues to be a sticking point.

The battle over DACA will remain under the spotlight as Congress continues to debate a long-term spending bill for fiscal year 2018. Several Senate Democrats, like Sen. Kamala Harris of California, say they will vote against a measure to fund the government beyond Jan. 19 due to the absence of a deal on DACA.

“This administration has made comments and suggestions through its policy that are very troubling. But at the same time I’ve heard from Republicans and Democrats that they want to see a way to fixing the problem,” Harris said. “I’m going to be optimistic until I actually read the bill and see what comes before the Senate for a vote.”