Conservative lawmakers are throwing up roadblocks to a GOP-only immigration enforcement funding plan. But party leaders are hitting the gas anyway, hoping to quickly flatten any skeptics as they race to meet a June 1 deadline set by President Donald Trump.

At stake is the final endgame of the 58-day-and-counting Department of Homeland Security shutdown. The Senate has passed the biggest piece of the funding puzzle, and top GOP leaders are now embarking on the multistep budget reconciliation process to sidestep Democratic opposition and fund enforcement agencies for the rest of Trump’s term.

Senate Majority Leader John Thune said Monday he would pursue an “anorexic” bill narrowly focused on Immigration and Customs Enforcement and Border Patrol. Republicans hope that will allow them to skip months of agonizing infighting — as they endured before enacting last year’s tax-cuts-focused megabill.

Still, some agony looms.

Sen. Rick Scott (R-Fla.) insisted Monday on spending cuts to offset the new enforcement funding. Sen. Tommy Tuberville (R-Ala.) said he wants to include money for the military and other GOP priorities. Sen. John Kennedy (R-La.) argued parts of a hot-button GOP elections bill should be in the mix. And across the Capitol, the House’s right flank insisted Republicans fund all of DHS through the party-line process — not just ICE and Border Patrol.

Thune and Speaker Mike Johnson are expected to discuss the path forward during their private weekly meeting Tuesday. The House is stalling for now on the bipartisan Senate-passed bill that would fund the bulk of DHS, waiting for progress on the second bill under discussion.

Even Kennedy, who said it was a “mistake” not to include parts of the SAVE America Act in any upcoming reconciliation measure, warned Thune against expanding its scope.

“If he starts making deals with individual senators … then he’ll have an avalanche on his hands,” he said. “I know a number of senators who will take a run at Thune and say, ‘Look, you’ll only get my vote if you include my stuff in it.’ Well, if he starts that, then I’ve got some of my own stuff.”

The ultimatums could start pouring in as soon as the Senate GOP’s closed-door Tuesday lunch, when Thune and Senate Budget Chair Lindsey Graham (R-S.C.) will get the chance to talk through the plan with their colleagues.

The first step will be for Republicans to take up a budget resolution — a fiscal blueprint for the party-line legislation, which Graham’s committee could release as soon as Tuesday. That blueprint is expected to task the Senate Judiciary Committee and Homeland Security and Governmental Affairs Committee with drafting legislation that would fund immigration enforcement agencies for the rest of Trump’s term.

Typically reconciliation bills include at least some attempt to offset new spending with other savings or revenue. But GOP leaders are ready to argue that won’t be necessary in this instance since it involves funding that would have gone through the appropriations process — had Democrats not insisted on enforcement policy restrictions after federal agents shot and killed two Minneapolis residents in January.

Thune also warned Monday that expanding the bill by instructing additional committees — such as the Finance panel, which deals with taxes and federal health programs — would expose Republican senators to politically tough votes that could threaten the overall package. Any amendment that is germane to a reconciliation bill and under the jurisdiction of the instructed committees is eligible for a simple-majority vote — and the minority party aims to use those “vote-a-ramas” to put the majority on the spot.

“It gets really complicated procedurally, politically, and so, you know, to execute on it — to do it with any speed — you’ve got [to] keep it really tight,” Thune said.

In a sign of just how fast Senate Republicans want to move, Graham is expected to skip a committee vote on the fiscal blueprint for the reconciliation bill, according to three people granted anonymity to describe private planning. While Graham indicated Monday he still hasn’t made a final decision, going straight to the floor would deny Budget committee members, including Scott and Kennedy, a first bite at making any potential changes.

Instead, Republicans are aiming to bring the budget resolution straight to the floor as soon as next week. That would give the House time to adopt it before both chambers are scheduled for a recess in early May, though it’s possible that timeline could slip — especially if Republicans also struggle to meet an April 20 deadline to extend a key surveillance program.

To get the budget blueprint or the subsequent reconciliation bill through the Senate, Thune can lose as many as three GOP senators, with Vice President JD Vance breaking a possible tie.

Republicans are closely watching one of their own committee chairs who will be tasked with helping write the bill, Sen. Rand Paul of Kentucky. He didn’t say how he would handle the budget resolution Monday but told reporters that he generally supports “spending less money, not more.”

Besides the grumbling from fiscal hawks, there are also Republican senators who are skeptical of any new reconciliation bill — especially appropriators concerned that the party-line approach is encroaching on their bipartisan turf.

But GOP leaders are cautiously hopeful they will be able to move quickly after months of sparring with Democrats over immigration enforcement policy frustrated many in their ranks. Senate Appropriations Chair Susan Collins (R-Maine) told reporters Monday her panel has been giving “technical assistance” to Graham’s panel while lamenting the breakdown in the appropriations process.

“It obviously would have been better if we came up with a bipartisan compromise to finish up the one remaining bill,” Collins said.

But the bigger threat could be in the House, where Republicans have an even tinier majority and a more rambunctious band of ultraconservative lawmakers.

One of their ringleaders, Rep. Chip Roy of Texas, reacted negatively to Thune’s “anorexic” vision for the funding bill Monday. He suggested funding all of DHS through a party-line reconciliation bill, not just ICE and Border Patrol.

“Well – he isn’t the only voice in this, is he?” Roy wrote on X. “We should move other priorities with ALL of DHS… we’re running out of time to deliver and to clean up these repeated swamp messes.”