A fight over how to pay for veterans' health care is the final big hurdle to getting a deal on a massive government funding omnibus, senators said Thursday. 

Negotiators have been working for weeks to try to cut an agreement on a mammoth omnibus — which would fund the government until Oct. 1, 2021 — and have until Dec. 18 to pass the bill, after using a stopgap measure to delay the deadline a week past Dec. 11. 

But lawmakers say they are still trying to resolve a stalemate on whether to count money for a Veterans Affairs health care program as "emergency" funds, meaning the spending wouldn't be counted under limits set as part of a two-year budget deal. 

"The omnibus is moving along. We're trying to work out the veterans health," said Senate Appropriations Committee Chairman Richard Shelby (R-Ala.). "That's the big one right now. It's the only big one."

Sen. Roy Blunt (R-Mo.), a member of GOP leadership and the Appropriations Committee, said the veterans health fight was the last significant sticking point. 

"I think that's probably the remaining sticking point, deciding how to count that VA Mission Act money," Blunt said, asked what the sticking point was for an omnibus. 

Senators are trying to figure out how to cover roughly $12.5 billion in funding for a VA health care program that gives veterans broader access to private doctors. 

If the funds are designated as emergency spending it wouldn’t have to comply with budget caps. If they aren’t able to designate it as emergency spending, they would have to find cuts to offset paying for VA healthcare. 

One option being floated is to fold the VA healthcare funds into coronavirus relief spending. 

The fight divides Washington along unusual lines; House Democrats and Senate Republicans have been supportive of allowing it to be designated as “emergency,” but Shelby said they were getting pushback from House Minority Leader Kevin McCarthy (R-Calif.) and Treasury Secretary Steven Mnuchin.

"They haven't said that. White House hasn't said anything. Mnuchin's against it and so is McCarthy. I haven't talked to the president about it," Shelby said. 

Sen. Patrick Leahy (Vt.), the top Democrat on the Appropriations Committee, also appeared to acknowledge that the VA issue is still a sticking point. He accused the president of claiming credit for the VA health care program but not adequately funding it. 

"Everybody agreed to put the money in, but now suddenly we don't find it," Leahy said. 

In addition to the VA health care issue, Shelby said McCarthy and House Speaker Nancy Pelosi (D-Calif.) are squabbling over a California issue: the Shasta dam. 

Shelby said he wasn't against McCarthy's push for funding for the dam, but "he'll have to work that out with Nancy."

The VA fight comes as the House passed a one-week continuing resolution (CR) to fund the government through Dec. 18. The bill still needs to pass the Senate, where squabbling is putting that timeline in jeopardy.

Once it is passed, leadership will then need to try to get an omnibus deal on all 12 fiscal 2021 funding deals passed by Dec. 18 or use another CR to buy themselves more time or kick the can until next year. 

"I have to believe the administration and the Republicans in the Senate when they say they do not want to shut down government. That it is possible to do the omnibus and we'll close there," Pelosi said of the omnibus talks on Thursday. "I mean, there's still some concerns, but that's the way it always goes."