(The Hill) – Senate Republicans are struggling to save funding for construction of former President Trump’s long-sought wall on the U.S.-Mexico border as Democrats press forward with plans to rescind nearly $2 billion in funding for his signature project.

Republicans in the upper chamber are pushing for the funding already allocated toward the barrier’s construction to be used to help continue progress on the project, a stalled effort that would likely take years longer and more money to complete.

Earlier this month, a group of Republicans — Sens. Mike Braun (Ind.), Ted Cruz (Texas), Mike Lee (Utah), Cynthia Lummis (Wyo.) and Marco Rubio (Fla.) — vowed in a letter not to back the annual appropriations legislation to fund the government if dollars are not set aside for the wall and implored their colleagues to do the same.

But not all Republicans are on board with the idea.

Sen. Richard Shelby (Ala.), top-ranking Republican on the Senate Appropriations Committee, cautioned against withholding support from a bipartisan deal, a move that could imperil funding for other significant GOP-backed priorities, including military operations and national security.

“If we reach an agreement on everything else and including defense, security, the nation, everything, I wouldn’t hold that whole [appropriations] bill and punish the military,” Shelby said.

While Shelby noted he’s long supported the border wall and said funding for the project is “important,” he said “funding the Navy, the Army and Air Force intelligence, all of that, is top priority to the nation.”

The issue signals a potentially tough road for Republicans to see the border wall project through amid spending negotiations, and adds to a host of issues leadership face in the weeks ahead as both sides of the aisle struggle to come to an agreement on government funding.

Last month, Senate Democrats outlined spending plans to rescind $1.9 billion in past border barrier funds allocated by Congress in previous years, months after President Biden called for funding for the project to end in his budget request for fiscal 2022. The plan was introduced as part of proposed appropriations legislation from the Senate Appropriations Subcommittee on Homeland Security. 

Biden, who campaigned on bringing an end to border wall construction as president, also put a stop to defense funds used for its development. The move came after former President Trump employed emergency powers to have billions in defense dollars diverted for the wall after failing to get full funding for the project from Congress.

Republicans have attacked the Biden administration for ending funding for an effort they, and the previous administration, argue has been effective in cracking down on illegal drug activities, border crossings and other crimes in certain areas where the barriers have gone up.

But top Democrats and critics have pushed back on those arguments, panning the prior administration’s approach to border security as ineffective and irresponsible. Detractors have pointed to how the barrier was constructed, costs for upkeep and damage to the environment during construction.

Specifically, Democrats’ plans propose using $50 million of the repurposed funds for “environmental mitigation efforts resulting from border wall construction” and come after the Trump administration fielded a string of lawsuits from advocacy groups in recent years that said the construction violated environmental law.

Brett Hartl, government affairs director at the Center for Biological Diversity, one of the groups that sued to stop the wall’s construction in 2017, said some of the damage was done in remote areas, where some border experts say the wall’s placement is not as effective or necessary as in urban areas.

“Very remote areas of Arizona and New Mexico, where there’s very, very few people, the closest town is 50 or 100 miles away. They’re not easy to access. You just don’t need a wall out there,” Hartl said while noting some of the permanent environmental damage brought on by the construction, including the decimation of mountains to help clear the way for the wall.

Earlier this year, Hartl’s organization saw a victory in its legal challenge against the Trump administration after a judge ruled the government failed to take a “hard look” at the potential environmental impact of the wall before building the barrier, according to Reuters.

Now, Hartl said the organization is hoping Democrats are able to follow through with plans to rescind the $1.9 billion in funding and help repair some of the environmental damage.

Though he said he expects some funding in the future to go toward routine maintenance for the existing barrier, which Biden previously said he won’t take down, he said the allocated funding is “the last big pot of money” still left to be diverted from the barrier.

In their push for the wall’s funding, Republicans and proponents have sought to draw attention to the ongoing border situation, as the nation has seen a surge in migrants at a border, to bolster their arguments for the system.

“I think many of the Republicans are concerned about the absolute chaos and disaster at the southern border,” Cruz told reporters when asked about his letter recently. 

Victor Manjarrez, who served with Border Patrol for more than two decades, also urged Congress to exercise caution given the current border situation, saying that while technology in more remote areas can be effective in buying agents response times, barriers have proved effective in other more populated areas.

“It’s not the only way. But it is part of the solution. It is one tool in the toolbox,” said Manjarrez, director of the Center for Law and Human Behavior at the University of Texas at El Paso.

Sen. Chris Murphy (D-Conn.), a member of the Senate Appropriations Committee, said many in his party care “about border security” but just “think that wall is feckless and ineffective.”

However, Murphy, who also chairs the Senate Appropriations Subcommittee on Homeland Security, said that doesn’t mean Democrats aren’t willing to negotiate on border security. “I’m willing to talk about funding for technology, funding for personnel, funding for other hard infrastructure.”

In their funding proposals, Senate Democrats detailed plans to repurpose the $2 billion in rescinded barrier funding for border security technology, including IT modernization efforts, expanded train capacity for Customs and Border Protection personnel, and the creation of three multipurpose facilities aimed at improving processing of noncitizens.

“We think there are other better ways to secure our border,” Murphy said. “So if Republicans want to shut down the government over a border wall, that’s their choice. But we got elected based on our promise to be more thoughtful about border security, and I feel like we have to make good on that promise.”

In the 50-50 Senate, Democrats hold a narrow majority when counting the tiebreaking vote by Vice President Harris. But in order to pass appropriations legislation, at least 60 votes are necessary, meaning the two sides will have to come to a deal on spending. 

As government funding lapsed for fiscal 2021, which ended on the last day of September, Congress passed a continuing resolution (CR) that allowed the government to be funded at spending levels set for the previous year, staving off a shutdown and buying lawmakers more time for negotiations.

The legislation allows the government to remain funded through early December. But Congress is expected to pass another CR shortly after they return from Thanksgiving recess next week, as the two sides have failed to reach a deal on top lines for spending amid ongoing disagreements.

Murphy said he’s spoken to Sen. Shelley Moore Capito (W.Va.), the top Republican on the Senate Appropriations Subcommittee on Homeland Security, about border wall funding. But Capito said she and the senator are “just at total opposite ends” over the matter.

“At some point, we’re going to have to sit down and try to either compromise the issue or go to a continuing resolution, which continues wall funding,” she said.