“I think for us to demand more would probably stop the whole deal,” he said.

The same GOP hawks who are losing out will likely be needed to help pass the deal, as McCarthy and his team deal with a revolt from fiscal hard-liners who sought even deeper spending cuts, revealing a deep divide among House Republicans.

“You have got to put together a package that can get the votes,” said Rep. Tom Cole (R-Okla.). “And there’s some Republicans that, frankly, see spending as a bigger problem than they do defense.”

The deal caps national defense spending at Biden’s fiscal 2024 request of $886 billion, a 3.2 percent increase. Military funding would go up by 1 percent in fiscal year 2025 for a total of $895 billion, effectively flattening the Pentagon budget over the next two years.

It would mark the first time Congress hasn’t added money to Biden’s defense plans. But not all defense-oriented Republicans are on board with taking a pause.

“I’m a ‘no’ at this point,” Rep. Michael Waltz (R-Fla.) told Fox News on Tuesday. “We needed to make deeper cuts on the non-defense side and, meanwhile, we’re accepting Biden’s defense budget, which is actually a cut.”

Beyond the politics of defense spending, there’s a practical effect: The Biden-McCarthy deal forces tougher financial tradeoffs because lawmakers will have less money to fund military priorities that didn’t make the budget than they would with another hike.

Lawmakers would need to trim within Biden’s $842 billion Pentagon proposal to find the $1.7 billion needed to purchase an extra amphibious warship that wasn’t included in the budget, but that Marine Corps brass argue is essential to its mission.

Congressional leaders also want to fund Indo-Pacific Command’s $3.5 billion wish list of items meant to deter China that was left out of the budget. And after a Chinese spy balloon traversed the U.S. this winter, lawmakers are clamoring to provide $266 million from U.S. Northern Command’s wish list to upgrade long-range radars.

House Defense Appropriations Chair Ken Calvert (R-Calif.) plans to save money by forcing Pentagon reforms, but said his panel must “do the best we can under the circumstances.”

“We’re going to have some tough decisions,” Calvert said.

Top Senate Appropriations Republican Susan Collins of Maine said Biden’s topline “is inadequate,” but added appropriators will craft their bills to levels prescribed by the deal.

“It doesn’t begin to cover inflation,” she said.

Sen. Lindsey Graham (R-S.C.), who quickly condemned the deal for shortchanging defense, hopes to rally hawks around an amendment to fix it. He called for raising the debt limit for three months while defense funding is sorted out.

“So when I hear Republican leaders say this budget deal fully funds defense, I laugh,” Graham said. “You’re not fully funding defense if you’re spending below inflation. So I will be on this like a dog with a bone.”

Graham told reporters he is proposing to add $41 billion to the Pentagon with his amendment, but it’s unclear if it could garner enough votes. Republican lawmakers may be reluctant to support a measure that would unravel the carefully constructed compromise, split their caucus or delay efforts to avert a default.

Other defense advocates contend that Biden’s topline — which still increases Pentagon funding — is preferable to the alternatives, including a default, yearlong stopgap funding and steep cuts.

“You can be disappointed and also recognize reality as it is, which is [controlling] one chamber of one branch of government will not yield the kind of change conservatives would like to see for the military,” said Mackenzie Eaglen, a senior fellow at the conservative American Enterprise Institute.

Lawmakers also see a potential relief valve in future supplemental funding packages for Ukraine, which would use emergency funding to bypass the caps.

“I think with Ukraine you’re going to have to have a supplemental,” Senate Armed Services Chair Jack Reed (D-R.I.) told reporters. He conceded Congress “might put some other stuff in too.”

Lawmakers could also revisit the agreement in a year and attempt to raise the spending cap.

“We will at the minimum be giving the Pentagon what they actually asked for,” Cole said of the debt deal. “And there might be opportunities for adjustment later. It’s just hard to tell.”